As far as I've noticed, SMS lacks two [important to me] things:
1) cue sheet support - when CD is ripped like one wav/mp3/flac file with cue file that contains track locations and information.
2) Autoplay option, that would turn PS2 with SMS into standalone player without need for TV [like it's currently] - so after SMS is started all is needed to do is to pop in disc or USB pendrive/HDD and SMS would start play all audio files in disc/usb drive starting from first folder and it would change folders like PSP XMB player does by pressing next when last song of folder is being played - just like any chinese DVD player with mp3 playback option. Of course, that autoplay option must be with possibility to turn it off in config.
SCPH-30003 bought for 5£ with disc read error, fixed
SCPH-35003 found in Sotland with disc read error, fixed
SCPH-70003 bought in Gamestation
PSP-3003, usually running 5.03 GEN-C
xbox 360, E74 edition