My GF and I rode it this weekend and loved it. She is not the biggest Simpson fan and she thought it was great and wanted to ride it again. Never had a baby powder smell on a ride before. There is so much going on during the ride that it will take multiple rides to catch all of the jokes and sight gags. My only complaint about the CG is they could have used a little more of the cel shading technique to make it look a little more like the cartoon. I liked BTTF but the last few years I couldn't ride it anymore because it would make me nauseous.
The Simpson Ride is a great addition to Universal and it will bring people to the park. Don't underestimate the popularity of The Simpsons. They have created a whole new set of younger fans thanks to the DVD sets and they will remain popular for many years to come.
If this is what we can expect in the future from Universal, then the next few years, between Disney, Busch and Uni, are going to be pretty awesome down here in Orlando.