The rip/tag/rename issues are by far the nastiest (apart from car install issues, which don't matter for Karma etc..).

The software that comes with the unit MUST be able to create quality .mp3 files, out of the box. An absolute MUST for an MP3 player (duh!).

The CDDB style databases get things tagged only approximately, and from there things are difficult to clean up. Slight mispelling of an artist's name ("Red Hot Chili Peppers" vs. Red Hot Chilli Peppers" vs. Red hot chilli peppers" ... ) causes no end of troubles, and is very difficult to correct (I can do it, but not using the software that came with my player).

Retagging the music has to be made really really easy, especially for the most common case of "the tunes are already on the device".

Cheers