[quote name='Hereticked']Is Ultramix really that hard?
I've gotten AA's on a bunch of the songs in Max 1 & 2
Even got my first AAA the other day

[/quote]
Ultramix is only "hard" because the 'perfect' window is very small, especially for freezes. You need to be super exact to get those perfects. Like you, I have no problems in Max or Max 2. Congrats on your AAA!
To the OP = different versions of DDR have different ways of scoring. Perfects, Greats, etc are worth a different number of points. To get an A, like someone said, you generally have to get close to a full combo and mostly perfects. AA's are usually full combo and mostly perfects. I've gotten 1 good and mostly perfects, and still gotten a AA.
There are a variety of forums and sites that explain how the scoring works in the arcades and home versions.
Just get as many perfects as possible and try to keep your combo (no easy task on Ultramix). Have fun!