After playing both this and Blur, I can't really decide which one is best.
They're both very similar style games in a sense that they're both intensely fun with plenty of things to keep you going.
I found the multiplayer more fun on Blur, as did my friends. I think it was more the Mario Kart style 'boosters' which made it slightly more familiar to us.
The cars on this could have been a little better, but the tracks and theme of it work well. Worth a buy if it's on offer.