Its a great game.
I have the PC version and its really enjoyable to play. Unlike gran turismo where there is more emphasis on realism it has a more arcade style to it so its not too difficult to play.
The difficulty curve is actually quite good, the races at the start are quite easy but necessary to get to terms with the courses etc as in the later races the cpu opponents can be very good.
Your car also takes damage, so you cant just drive around fullspeed like in gran turismo and bounce off other cars. Well thats a lie, you could, but you may find that you are unable to turn left/right later in the race due to the damage caused!
We all make mistakes as well and for that reason you dont need to repeat the whole race just because you crashed too hard into a wall in the last lap - you can travel back in time and attempt that bit again. Adds a nice touch to the gameplay.
Very nice graphics as well. The user interface is one of the best I have seen in a video game.