Absolutely addicting on line. Beautiful graphics and great single player. There are only 8 courses but what it lacks for in single, which is still awesome, it makes up for in pure amazing fantastic seductive on line play. If you own a ps3 then you should already have this game.
I must start by saying I am terrible at racing games. I can never keep the car on the track. However in this game THERE IS NO TRACK! woo hoo! OK :-) so I personally like driving as a "trophy truck" as they call them in the Baja race. I love running over motorcyclists and other cars. This is a great "I had a rough day at work" relaxation game if you ask me, and so much more legal than running over your boss in the parking lot on your way home :-) Not being a "racing game aficionado" I can't really tell you how realistic the game play is. I would say it's less realistic than F1 but MUCH more realistic than Ridge Racer. I kind of liked the "motion sensing" controller option for this game it allowed me to use the controller like a steering wheel, but I went back to button mashing pretty quick. I also noticed that damaged scenery, tire tracks, etc. stay from lap to lap which is a nice bit of realism. When you wreck as a motorcycle driver the body flying has some nice rag doll type dynamics to it too.
High points: Graphics are great, tracks have different paths depending on your vehicle. Crashes are fun to watch, but distract from the racing.
Low points: No rumble, which I miss particularly with driving games. I didn't get much of a sense of speed with the vehicles. Motion sensing did not make up for this, as I preferred driving with the analog stick. There's also not much of a sense of accomplishment when you win, the A.I. seems to always be right behind you (rubber-band A.I.) And despite the variety of vehicles, this starts to feel old and repetitive pretty quickly.
People that enjoy it seem to prefer multiplayer, but from what I've read on message boards, geting into a multiplayer game can be a tedious process.