I also remember iTunes (despite it's fall from grace later on) to be miles ahead of any syncing app. The difference in just plugging your iPod in and choosing which music to sync vs. erasing/reformatting/error-handling transfers to your mp3 was lightyears. That was part of what did it for me.

Also, on the iPod you could browse your music in an organized fashion (e.g. by artist), whereas with other mp3 players it was just a long list of tracks.