Has any one tried Rockstar Games' Beaterator?

I've been waiting for this for a while as I like making music. I noticed it in the app store but without any reviews yet. The description isn't great and the pictures don't explain much.

Has any one actually downloaded it? Looks like an interesting game but I'm not the kind of person who fills their iPhone with apps I have to pay for, as they never tend to have a good shelf life.

Any one got an opinion on it?

Thanks