I can understand why some people don't like the werehog levels since they aren't really that "Sonic like", but I enjoyed them quite a lot. It's fun going around and killing everybody in sight, though when you have to be very accurate in order to avoid falling down it's not that unusual for the camera to mess up everything, causing you to die. Or in cases when you'd just wanna see around you but the camera is kinda locked to the place, giving you no chance to do so.
The Sonic levels are awesome. Okay I have to admit, some of them are hmm, annoying to say at least, but mostly they are pure gold. It's all Sonic - going damn fast collecting rings. Almost like the old Mega Drive games.
The graphics are quite stunning and a lot better than the Sonic the Hedgehog (Xbox 360. Why didn't they name it a bit better) game had. And it's definitely a BIG plus that you can download the original Japanese voices to the game.
And yeah, btw. I think the RPG style game design is just freaking cool. The "Select-your-stages-from-the-list/you can't select the stages at all, we just give them to you"-gamestyle fits the 2D games, but with a 3D game it'd just be annoying and pausing the game too much.