I bought one because my SG broke a while back. It works surprisingly well for a 3rd party controller. The fret buttons have more travel (they stick out more from the controller) BUT they are incredibly sensitive. You hardly need to apply any pressure to them. My whammy bar is only slightly tighter than the SG's, but I can still whammy as fast as I can with an SG.
My only complaints are that the strum-bar isn't 'clicky' like the SG's. Again, this is very sensitive though, so the slightest press on it strums the guitar. Also, because of the shape of the guitar, I had to change how I hold the guitar. The place where I used to rest my wrist on the SG is gone, so I just adjusted my grip.
Because all te the buttons are so sensitive, it's easier to do the fast solos without as much strain or effort. Overall, it took me about a half-hour to get used to the new controller and now I am able to play BETTER than I can with the SG.