Wow, this really is a polarizing game. Let me tell you my experience. I knew of the problems with the Uber Tricks going into the game...I also knew the people that truly gave the experience a try loved the game.
So I rented it, because I wanted to see if it was truly that hard, or if 3rd parties can do Wii games right. I found Uber Tricks to be extremely difficult to do when you are in the heat of racing and you just want to implusively pull one off. So, I practiced in the Uber Trick practice area, which was very nice addition. Soon, I could pull off the Heart, Circle and Z Uber perfectly, so I just used those all the time.
Racing and Boarding felt better in this game than any other SSX I played, but I never felt the satisfaction and drive to push myself further like I did in SSX 3. I think this is because the levels, were not nearly as great as 3, even though a few of them were the same levels.
I actually really loved the new artstyle and direction and felt it was a postive change for the game. Overall, I had postive feelings for the game, but just never pushed myself to the buy category. Sometimes I want to go back to try the game again, but not enough to do something about it. If the game had waited and came out with online racing, I think I would be in love with the game. I actually like the difficulty of the tricks for online competitive play.
Oh, about tricks, I dunno why the poster above was mentioning flailing around while doing regular tricks, I never had that issue. Simple small movements worked fine. In fact I thought regular tricks in this game were easier in many ways than other SSX games.
The game is an above average game with a learning curve that will be small for some and large for others. The game is deep and rewarding, and if you get into it really feels right. Specially just the boarding around aspect.