I will rent it and get a feel for myself... but one thing is clear from watching different walkthrough of this game: if the player sucks at controlling Sonic, the game seems boring, broken and too difficult; if the player is good at controlling Sonic, the gameplay and level design seems fine and the game seems fun.
If you compare these two playthrough videos and then watch Gamespot's video review, it's clearly visible that the reviewer just sucks at controlling Sonic and understandably he didn't like the game and found it too difficult.
The bad one:
http://www.youtube.com/watch?v=Y-94tVXPWMg
The good one:
http://www.youtube.com/watch?v=dIg9cB1HYHg
Gamespot's review:
http://www.youtube.com/watch?v=qsEvBiLNPFo