iTunes is better with AAC than MP3 IMO.
That being said, Exact Audio Copy with the Lame encoder does MP3s better than iTunes and its MP3s at the same bit rate sound better than iTunes AACs (all in my opinion). However, iTunes is MUCH easier to use.
Coming from someone who has ripped over 20 GBs in the last week.

I love my new iMac!!!!!

LIFE IS SHORT.
DON'T BE A DICK.