what is ogg?

i've had soo many people tell me that ogg is better than mp3, how? i know ogg is opensource, but as long as the bit rate's the same does it really matter in terms of quality? or does the differnce matter in size ?

AAC is a bad choice for a musical format.

What? AAC is a perfectly fine format, especially since there aren't really any well-tuned encoders yet. Apple are doing pretty badly with it since they don't have real ABR or HE-AAC (which beats Vorbis at low bitrates), though.