I'm occasionally experiencing cut-off MP3's when I hear them for the first time in the car. The track time is ok, but a bit of the end isn't there. When I then go back to the WAV (if it's still on my harddisk) it sounds ok.
I believe this is actually a known problem with the current player software which will be fixed in 1.1 (like everything else ). 1.1 has a new mp3 decoder, from ARM I believe.