I am asking from a functionality standpoint.

Online music collaboration needs to be as easy to share files and communicate as possible. So lets have a look at some of the pros and cons of both compression formats:

PROS

CONS

So there... I am going to suggest that people should not have to choose. They should use both. First upload the mp3 version of their track and then use the Attached audio files
Existing audio file: field to attach an ogg version of the track.

Hope this makes sense to you??
If you wold like to comment or ask questions please feel free!

p.s. I am going to publish this as a forum topic and an FAQ to make sure the message gets out.