I picked it up a couple of days ago, my first impression is that the fights are harder to win than in the original UFC game. Also I'm not super keen on how they do the attributes for your career fighter, in the original game you could just apply points you got from fights and training directly to the stat you wanted to increase, now you have to play the mini games for training in order to improve the attributes. I mean it's probably more "realistic" but if my character is a boxer, I don't want to focus on submissions.
Customization isn't nearly as robust either, you don't get a wide selection of shorts or walkout stuff. Tattoos are better this time around though, as are things like hair, facial features, etc.
I do like how they improved the fighting mechanics though and there's more to it now then just mashing buttons.