I downloaded the UFC demo on PS3, and I'm quite surprised at how fun it is. Though the tutorial seems to go on forever, the controls actually aren't that bad. I wasn't sure how they could cram everything in (striking, clinching, throws, guard, submissions, etc.), but it actually works quite well.
The wife and I played it for over an hour Monday night, which is saying a lot because she's definitely not a gamer, though she is a big UFC fan. She kept knocking me out using Chuck Liddell's superman punch!