UFC is extremely robotic, very simple. No upper body movement, no head movement, striking is very basic. Reminds me of Fight Night round 1 or something.
FN4 is way more advanced. The physics alone make it a better game. Watch how punches glance of gloves, the side of your face, arms getting tangled, etc. Punches are based on where they land on the target (for example various points on the head like temples, cheek, chin, nose, etc) and timing, which add realism. UFC doesn't have that, it's basically hit high/low & that's pretty much it. FN4 has some of the best game physics to date, in any game. The legacy mode is also way deeper than UFC and the Online play is better.
Now a lot of it is based on what you like more, UFC or Boxing. But if you put that aside and just compare the actual make up of the game, the physics, etc. FN4 is better, there really is no comparison, which is why FN4 has received better reviews than UFC.
