I have two GG&G and I have not had a second's trouble out of either. Make sure you have the right rail on your pistol. All of mine are .45 so since their frames are larger maybe that is the reason I have had no trouble but whether on Compact or full size, they have been working for me. I also have the Surefire, too expensive and not one bit better than the GG&G, as well as the Pro-Mag. It works but hangs the light down too far. I did a picture post on here and on HKPRO comparing the three.
In summary of the post, if money is a major concern, Pro-Mag will work just fine. If money is not a concern, IMO GG&G is the best for the buck, if you must have the Surefire name and have the bucks, then their adapter will work just fine. It looks almost identical to the GG&G.
The new adapter from LaserMax is the about mid cost between the ProMag and GG&G, looks like the GG&G, but I do not have one and I doubt I will be buying one. I am just not in the market for any more rail adapters.
I have used them on Compact 45s and Tactical 45s with the TLR-2 and they have not marked the frame or shifted any at all, none of them.