I went and picked this up today to check it out... it's pretty weak.
It is basically a clone of fight night series but with a lot less control of the fighter.
What really turned me off was that Dana White shows up immediately after the career mode starts and seems to follow you along throughout the career process. It'd be like buying Madden and having Roger Goodell walking you through training.
UFC and White seem to have rushed this title out pretty fast.. My expectations were not very high going in, but I can honestly say I've never played a worse game on the PS3.
(On the other hand, Call of Duty Modern Warfare 2 is unreal...)
The standard fighting portion is pretty cool, though... no Dana White in sight.