I do not pull directly against either clamp, but have experienced just about everything as posted on this board. Have had the Gamma slip when used as a bridge (oil/string residue), had one plate fall out, have seen that the pads gum up quickly and require cleaning more often than the GSS. I still use the Gamma, but now never as a bridge. I like it for use when tightening knots, but outside of that I'll reach for my GSS clamp.
Having had one pad fall out which I've since glued back, was glad that I had two clamps. Could probably have improvised, but have decided I'll purchase another GSS, have a feeling that one or the other pad will drop out at any time.
One other advantage to the GSS is that you can take it apart, something that I would have really liked while attempting to clean, and then re-glue the Gamma. Although just thought that I'd check this feature out on my GSS. Didn't have much luck but didn't attempt to pound too hard either.