It's a really good game but has a ton of bugs. I played through most of career mode and noticed that the announcer's accuracy is not really any better than the demo. There are still clipping issues (first knockdown I scored since purchasing the game had my fist go through my opponent's head).
The advertising is not as bad as some people make it out to be. It actually makes it more realistic...like watching it on TV.
The online mode is somewhat laggy. It is not bad, like Call of Duty, but it is noticeably not as smooth as single player. It doesn't really detract from gameplay, but it is noticeable.
I've played a few online fights and have noticed that some boxers are totally overpowered for the weight classes they are in. The balancing still seems to be pretty far off. Power punching is still the way to go, and Jake LaMotta's flash ko body punch is a little too fast...
That aside, the multiplayer is a lot of fun and VERY competitive. It is probably the most competitive game i have ever played since it is one on one. You cannot rely on teammates but rather your own skills.
I wish the career mode was a little bit better, but it isn't terrible like some are claiming. The training mini-games are pretty annoying though. I wish they would combine some of them rather than force you to focus on one area. It is really hard getting your fighter to LOOK (shape-wise) how you want him to look and still have his stats be competitve; however, with the character creation process, I was able to make my virtual boxer look almost exactly like me! The jawline / chin feature is the only one that is lacking from last year...this year it is not really as customizable in that area and is harder to get it perfect.
Maybe I'll post some comparison pictures once I get my digital camera warrantied...it's pretty unbelievable.