I just got a couple of these to try out here; both for Gen 4's. I too was skeptical because I've had great success with the G's stock except for occassional slide bite with 19s or 26s if I got a little to high during a draw.
But DocGKR, Bill Rogers, Ken Hackathorn et al reviews just created critical mass to give them a look. Feels ok to me. Haven't shot it yet.
I do find it mildly amusing that the method of attachment which is widely mocked for Gen 4 grip size adaptors is complimented when attaching a Grip Force Adaptor. People are funny. ;)

