In my opinion, NO. I am very dissapointed in the new game. I guess after all the hype and all the waiting, I thought it would be better.
The quads are for lack of a better term, lethargic, but I guess that's what you get with 4 strokes. I have only had a chance to ride the YFZ yet, which I thought was boring to ride and I've heard the others are even worse. The hill climbs are the only real highlight of the game for me, and that's if you can keep from getting run down by the buggies.
If you are looking to spend $40, get GT4.
I would actually go out on a limb here and say ATV3 is better.