The first thing you'll notice about Carbon is that the graphics do not impress. Second thing you notice is that despite lackluster graphics, the framerate is incredibly choppy. I'm really surprised how bad the game performs. Then, you get into the actual gameplay and you'll find it to be just like other recent NFS games, which means a lame, unnecessary story (with many non-skippable cutscenes), and an emphasis on flash over substance. It's essentially just like the previous games except they've piled on more fluff like taking over territories and haing wingmen. Expect EA to some day release a "real" NFS game at which point they'll pretend to be brilliant for deciding to "take it back to the basics". Something they should have never left.
It's not that this game is that much different than the PS2 version, its that there isn't that many games on the PS3. The graphics are good and the gameplay is sound. If you are a fan of the NFS series this is a must play!