Cons: Backlit lcd, no line-out, hardware glitches, lack of quality control.

Summary: I have owned this unit roughly a month. It has wayyy too many things wrong with it for me to justify the price. One, it has no line-out, which is unforgivable, and the headphone jack is on the front which makes it impossible to mount in a car and make it look good. It also gets really hot underneath when the dc power supply is used. The LCD is backlit blue and looks good, but is really hard to read off-axis. The backlight turns on for about 4 seconds when you push buttons, and then turns off. I think they should have a backlight switch so you dont waste battery this way. The backlight quit working a week ago, so its a moot point anyway. The buttons also beep when you push them, something I find annoying, and the unit beeps when you pause it, something I also find aggravating. The point of pausing it is to NOT hear anything. The units headphone jack is also incapable of driving higher-impedance headphones like my Sennheiser 535s, so you are forced to use more efficient ones (like the crappy supplied earbuds). One of the most aggravating things wrong with it is this glitch in the ID3 reader that takes the last part of whatever the artists name was before the artist name that you are viewing, and tacks it onto the one you are viewing; if the first artist you viewed was Matchbox 20, and the current one is REM, the ID3 readout will say REMchbox 20. The unit also has a display switch, but it doesnt remember your choice, thus, it displays this unneccessarily long filename whenever you switch tracks. The ergonomics are poor, and are hard to use if you use the belt clip. The ESP also turns on whenever you turn the player on, which wastes batteries if you forget to turn it off. The volume control is also recessed, which makes it hard to adjust, and the thing blows through batteries like nobodys business. You can expect maybe 6 hours on standard alkalines.

So whats good about this player? Not much. The backlight looks cool (when it works), and the player has good skip protection even when the ESP is off. It does read ID3 tags, and the belt clip is cool. Since I am currently on my second player, which also does not function properly, there is no way I can recommend this unit. I actually liked the player when it worked, but it has too many unforgivable flaws to be sold as a production unit.

I only rated it 4 stars because there are several annoying shortcomings that quickly become apparent. Probably the biggest is the peculiar way the "resume" feature works. The problem is this feature only works when the power is on. So even though I have the car kit which lets the player run off the cars power, I still need to remember to stop play and then turn the unit off. Were I to simply turn the car off, the resume feature wouldnt work.

The other big annoyance is with fast forward or reverse. They are simply too slow to be of much use.

This unit has GREAT sound quality. Rich, warm sound. The build quality of the unit is great, compared with others like the Rio Volt -- very sturdy. It supports AAC (Advanced Audio Coding) files, of which I made quite a few with the Psytel AAC encoder. AAC sounds FAR better than MP3, even at low (128-160) bitrates. I was really shocked and surprised. Its also a rather attractive unit -- nice deep burgandy color. Folder and file navigation is also very easy and intuitive.

Now... whats wrong with it?

Resume doesnt really work. With MP3 CDs, it only works if you turn it back on within about a minute of turning it off. And it does work -- it goes back to the precise spot in the song you left off at. However, if you turn it back on longer than a minute after, it starts back at the first song on the first album. With AAC-CDs, it goes back to the same song, but at 0:00. And after a minute it goes back to the first song on the first album. This is a fatal flaw, as far as Im concerned.

Between-track gaps: with AAC CDs, its actually quite minimal, like 1 second or 2 between songs. With MP3 CDs, especially if you have 200+ songs, it can be as long as 5-8 seconds. Completely unacceptable, as far as Im concerned.

Seek times: with fewer than, say, 100 files, its quite quick. After that, though, it can take forever to find certain folders.

Filename display is very buggy. I rarely use ID3 tags on MP3s I make myself, so Ive not seen the "overwrite" error that a lot of people talk about in their reviews. But the filename display is buggy as well -- lets say a track is called "01 - Five years.mp3": the Expanium will display "01 - Five years 3456789012345678901234567890". Even if you have, like the manual suggests, short filenames (even DOS 8.3 names!), it will still display the numbers. Not a big deal, but it does detract from the aesthetic appeal of the unit.

In short: I think this unit has too many shortcomings to be recommended. I give it 3 stars simply because of its potential (AAC support) and the superb sound quality. Sonic Blue/iRiver: are you listening???

I turned to the Expanium 503 after having a Rio Volt 250 give out on me after a month of use. Im happy with the Expanium, whose sound is better, and whose controls are much simpler and logical (though not having as many bells & whistles as the Rio Volt), but there are some problems. As youve read earlier, the MP3 labels get garbled in the readout window, but this is something I can live with. Whats more serious is its erratic inability to recognize certain MP3 discs. The discs Ive burned myself are sometimes played by the unit, but at other times it will grind away and the readout window will say only "DATA" and refuse to play. If this happened all the time, Id blame my method of burning, but sometimes it fails and sometimes it plays the same disc perfectly, so I blame the unit. I intend to return it for another of the same model under my replacement contract. After my experience with this unit and with the Rio Volt, I strongly advise you to spring for the extra bucks and get an available maintenance/replacement contract with your retailer. Once bitten, twice shy. Twice bitten, very very cautious. This is relatively new technology, and there are going to be a lot of failures before some manufacturer finally gets it right. Good luck.

"ADDENDUM: ID3 tags seem to work on my unit now, but with an amusing bug. The tail end of the tag does not fill the remainder with spaces; the old characters stay. So right now I am listening to General Publics song "Tenderness", but the artist tag is "GENERAL PUBLIC ND", and the title is "TENDERNESS 90, GO OU" (the last song played was "C30, C60, C90, GO", and there must have been an earlier song with "OU" at the end.) Kajagoogoos "Too Shy" is now "KAJAGOOGOO LIC ND" and "TOO SHY SS 90, GO OU"."

* The unit is thin (a little over an inch) and light, unlike most of the MP3 units Ive looked at.

* I have had no problem with the "Resume" function on MP3 files; however, if the unit "goes dark" the "Shuffle" indicator doesnt come back when you start it up again. It seems to lose the Shuffle setting. If you hit "Start" and then immediately press the Mode button to choose Shuffle, the unit changes the mode but then does not start. Just press "Start" again, and youll resume where you left off.

* The unit does recognize ID3 tags, but only some kinds. The files I got from mp3... work with the "Artist+Title" function, but the files I have converted with MusicMatch do not. Maybe it recognizes ID3v1, but not ID3v2. I havent been able to get to Philips web site ...to find out.

* I havent found software to create AAC files yet. MusicMatch is supposed to have a deal to add it, but I cant find anything on it on their web site.

* The "fast-forward-within-track" also works on MP3s, but it doesnt seem to speed up; it runs at about 6x normal speed.

ADDENDUM: ID3 tags seem to work on my unit now, but with an amusing bug. The tail end of the tag does not fill the remainder with spaces; the old characters stay. So right now I am listening to General Publics song "Tenderness", but the artist tag is "GENERAL PUBLIC ND", and the title is "TENDERNESS 90, GO OU" (the last song played was "C30, C60, C90, GO", and there must have been an earlier song with "OU" at the end.) Kajagoogoos "Too Shy" is now "KAJAGOOGOO LIC ND" and "TOO SHY SS 90, GO OU". Not a big deal to me, though.

I already had an MP3 cd with the albums in their respective directories, so I was afraid that the player would not be capable of handling this, but to my surprise, and joy, it recognized it, and it makes each directory an "album", making it easy to browse the 200+ songs I had on my CD.

Additionally, I have not yet been able to get the player to skip. Although the earphones that came with it are not to my liking, that is easily changed. With the handy midpoint controller on the headphones, you can easily chose ones to your own preference without having to worry about a compatible remote on them.

Although I prefer the look of the Rio Volt, it was not worth the extra wait.

My highest recommendations for this player.

Still I found it unsatisfactory for 2 main reasons that made me reutrn it:
- The Amazon.com description reads: "Includes AC adapter and 3-key remote control" but no remote is included. Double checking in the manual revealed that the remote is an optional item.
- The headphone socket is very loose so that the headphone plug slips out way too easily.

Its features are excellent.... the first thing I did was download an MP3 ripper and an ID3 Tag creator. All freeware. I ripped the entire collection of U2 Albums and put them onto 1 CD. When you run the player it tells you each album name and when the track is playing it displays the artist and track name on the screen, if they fit otherwise the track name.
The quality is average maybe slightly above, but I have heard better.

They ship Philips headphones with it.... they are [bad] buy new ones.

The only negatives:- headphones [bad], screen is hard to read in poor light (excellent in the dark and bright light) and the resume function doesnt work on Mp3 discs only CDs.

Buy it its worth it!

Since I commute about 2 1/2 hours a day an MP3 player really appeals to me. I bought the 503 after returning 2 Rio Volts in one month. This unit is not as good looking (purely subjective) but works much better, is quieter and louder. To clarify, I use mine in the car and it doesnt whine and "thump" like the Rio. However, the cassette adapter that comes with the unit doesnt make good contact with my stock Honda cassette player heads so I use the one that came with my old Aiwa CD player. MAN! What a difference in VOLUME! The head on the Philips needs to stick out further (like the Aiwa). Its pretty easy to use, has a cool metallic black/purple finish and the best ear-buds Ive ever used. Its easy to navigate and has a fast-forward (not Rio). The display is difficult to read in sunlight, impossible to read with polarized shades on, but is pretty cool at night. So, I plan on using this unit happily, until I can afford a Remote Solutions PJB-100 (20 Gig hard-drive). The only reason I didnt give it 5 stars is the cassette adapter.

This thing is great. I am quite familiar with MP3 and I try to keep up on the latest technology and I must say that the one most important feature of this player - sound quality - is extremely excellent. All of my MP3s are "archive quality" (IMHO!) and the Philips does an admirable job of reproducing them. Most of my MP3s are variable bit rate, many with BRs ranging from 12 - 320, and I have had no problems there. Needless to say this was a big selling point for me. The ID3 feature (which recognizes artist & song info) is also excellent, as well as the interface, backlight, speed of song title recognition and startup, and included accessories. It is also very compact and light. About the only complaint I can come up with is that it does not include a case... personally Id like to see a small case befitting this beautiful little player. Needless to say most of the CD player cases out there are bulky and ugly, so I had to create one out of a CD disc case. Ah well, one can dream...

As far as the color, as others have mentioned it is not black, but more of a purple color. However, I like it! Black is so... black. The purple is something of a pleasant change and has a nice iridescence to it.

flaws are the following:
the buttons, like the other user noted.
the color IS NOT BLACK! its like a dark maroon, and it somehow contrasts when in light.
when searching for songs, you better remember the numbers!
when searching and finding the song, be ready to wait for about a second to load.

everything else is great.

Display has three modes: album, filename and ID3 tag.
If you burn a CD with folders for individual artists (or styles) the album mode will display the name of the selected folder on your MP3 CD.
The filename mode will scroll the individual filenames but only the first 40 characters. I really like this feature since a lot of my MP3s do not have decent ID3 tag info and I was dreading the prospect of having to go in and update them all.
The ID3 tag mode is just what it implies but I found myself not using this feature at all since I can just look at the filenames instead.

I was impressed with the EXP50317s speed in reading and searching MP3 CDs; a friend of mine has an older Philips model which is a lot slower than this one. Also, I havent experienced any skips or hangups during play or while changing tracks.

Sound quality of the player is very good for both CDs and MP3s and the car accesories make it a very nice addition to your cars stereo system. Plus now I can finally listen to all my MP3 while Im driving.
The only thing I dont like about the EXP50317 is the fact that the control buttons have a chrome finish which makes fingerprints and smears on the buttons very visible. A matte finish for the buttons wouldve been better.
Overall, I think this is an exceptional player and, although it wasnt cheap, Im glad I spent the extra money. It was worth it.

Bonus points for some rocking in-ear headphones that have some new BASS technology. Batteries are NOT included contrary to product description. Im using NiMH rechargeables. The included car kit works as expected.

Thanks Philips!!

Update in Feb. 2002: The MP3s stopped working. Music cds still play but the mp3 discs just sit there. So Ive returned the player to Phillips for warranty replacement. Currently awaiting the new one. Rating dropped to 4 stars.

Got the replacement model from Philips after a couple of weeks. So far so good.