Many people have complained about the controls. I'm sorry to say that they are totally, totally wrong. Carbon provides you with several control schemes, involving gestures and buttons, all of which come with three sensitivity settings. The upshot being that there is definitely a perfect control system for you.
As for the game itself, the gameplay is pretty much identical to NFS Underground, Underground 2 and Most wanted. IE the game is still very fun to play but has nothing really new to it. The police chases are still there but there aren't as many (you don't need to complete chases to advance in rank this time).
Interestingly, this incarnation of NFS is much shorter than previous ones. This means that there are fewer cars available but the game is a sensible length instead of the weeks it took to complete Most Wanted.
My one big criticism of the game is their allocation of the cars. There are three car types, Muscle, Tuner and Exotic. The Muscle cars are stuff like the Mustang and the Dodge Charger which no sane person would touch with a barge pole but the Exotic cars, stuff like the DB9 and the Porsche 911 handle terribly - they just don't turn corners. This gets frustrating because if you want a car that handles well, you're forced to stick with the Tuner cars.
This turns out not to be a problem as the Tuner cars have the Skyline R34, the MR2 and the Subaru Imprezza but it's a shame to have the excellent selection seen in Most Wanted messed with.
Overall, its still a very fun game, especially if you don't yet have a racing game for the Wii. I'm not sure it's worth £30 but if you see it in a sale, go for it.