Honestly, at this point it looks good if your GPU is underpowered. Seems to be of little use if you have up to date, decent hardware. Very typical of new technologies. I would wait a few months and take another look.
As far as I can tell, there is NO increase in framerate, just in "responsiveness". I have tried Skyrim with it turned on and off and I cannot tell the difference.
Note that they talk about avoiding tearing of the screen and input responsiveness, nothing about increased framerate. Me, I thought that what the damn thing was for: to combine the power of two graphics cores. Gypped!