Definetly NOT a terrible game. It is in fact one of the best realism-fighters on the market. In my opinion it is more enjoyable than Fight Night, but I am biased as i prefer Mixed Martial Arts to pure Boxing.
In this game, you get to create your own fighters, choose their styles, attributes and of course looks and trunks. It has a fairly deep career mode, and plenty of exhibition/xbox live modes.
I encountered nearly no lag while playing online.
The feel of the game is what makes it so fun, it just feels right, landing punches and kicks. It feels natural, as if your characters limbs are actually impacting on semi-soft flesh.
Very good physics in other words.
As for the graphics, they are great. The lighting is a bit spartan, there is no remarkable sci-fi lighting setups here, but the fighters themselves look very realistic.
Some of the best skin shaders ive seen to date. The upcoming Fight Night 4 seems to have slightly prettier shaders, but a bit too wet if you catch my drift.
In UFC 2009 your fighters actually look dry, like normal humans. As they sweat you see individual droplets crawl down the body, creating a trail of shinyness :)
Of course this applies to blood as well, which has a habit of staining the floor during heavy fights.
Overall, a clear 4 out of 5. A perfect score would indicate that the game is as perfect as it could have been, which i'm not ready to say after just a few hours of playing.
If you like realistic fighting games, and are tired of the endless pounding in boxing or the endless hugging in wrestling, this is the mix for you.