if you're an NBA fan you should be planning on getting this game, simple as that.
anyway, the website's in italian but the video is pretty good (and in english).
The noticeable differences are mainly aesthetic, the player graphics look tweaked but they look a little like the live characters (where everyone is sort of hunched over and really angry and dark-eyed) but it's hard to tell from just this little video. the player animations are better (inc. the KG chest pound) and to my surprise the commentating is different (obviously its going to be different this year but it was mostly the same even during the demo's they released on live for 2k8 so its cool to see they'r showing it early) - also, the best feature by far, Cheryl Miller is in the game!!!!!
anyway just go check the video for yerrself ya digg!