People stuck in the past can't accept the fact that Sonic Team has decided to go a different direction.
The story is simply lame. There is no reason you need to pay attention to the story, nor do you need to know what's happening. It's a Sonic game. Get through the level, got it?
Gameplay : Controlling Sonic is just about the way it has been in the past 3D Sonic games, and there are times when I think his speed is sufficient. His controls are far from perfect, but passable. Controlling Knuckles and Tails during Sonic's Story however; will make you want to cry.
Controlling Shadow is also about the same as it has been in the past. His sidekicks are also about as annoying to control as Sonic's.
Controlling Silver on the other hand, is what makes this game worth playing. Sure he isn't fast, but his Story is probably the only one that's genuinely fun to play. Amy and Blaze also control surprisingly well compared to the other characters in this game. If anything rent this game and play it solely for Silver (I admit, I hated when they announced him, but he is NOT another Shadow [which they should really have let die after SA2]).
Graphics: The first game which I noticed for the XBOX 360 to have 1080P listed as a supported resolution on the back of its case. The graphics are good for a Sonic game, yet not so much for an XBOX 360 title. Taking into account that it's a Sonic game and that some cutscenes within the game are truly spectacular looking, the graphics get my aproval.
Sound: It's a Sonic game. Expect craprock and some kind of technoish stuff. Ring sounds, robots exploding, yadda yadda. Been there done that. Voice acting isn't nearly as bad as people claim and is in fact much better than pre-4KIDS Sonic games.
Value: Not for everyone. 3D Sonic fans will defend it to the death. 2D Sonic Purists will whine that it's not like the originals. Where do you sit?
Overall worth a rent for a runthrough of SIlver's story, explore the rest of the game if you don't mind to lackluster controls and storyline. There's plenty of missions and ACTs to complete. Obtaining S-Ranks on all of them will frustrate you due to camera issues which have plagued the series for almost a decade.