I'm not the OP, but in 2003 iTunes was the single biggest drawback to switching to the Mac, for me. I had a fairly large collection of MP3s at the time -- maybe a coupla thousand -- and a bunch of versions of the same song in some cases (an album version, a radio version, live at here, live at there), and it was all neatly categorized in the filesystem, band/album/name, when I switched from Gentoo to OS X. I freely admit I should have had a backup.

When I "tried" iTunes, there was an option for it to rename all your files (I don't remember whether it was the default or if I stumbled on it), but what I did NOT expect was that all my carefully named folders and files would be lumped into "Unknown Artist"/"Unknown Album"/"Unknown Track NNN".mp3, while my old files were all carefully removed.

My MP3 collection literally never recovered. I could choose to play the few hundred tracks that had happened to have good ID3 information, but all the tracks I'd ripped myself were essentially randomized. I also never found an ID3 creator that could successfully differentiate the various versions of songs I had, though I stopped trying around 2006 or 2007, and now I don't bother buying music any more -- I just listen to Pandora.