I've got a G20L and Power Pistol works very well in the longer, 6" barrel giving me a few hundred fps faster velocities with both 165 and 180grn bullets over my neighbor's stock G20. Further, I've got no issues with max loads of it showing any pressure signs. I've got a nuclear level load that just shows a bit of primer flattening but produces 165grn velocities approaching 1,600fps in my 6" G20L. All my Power Pistol loads include LP Magnum (CCI 350) primers as not only do they produce higher velocities but lower SD and ES than regular LP primers.
ETA: I've found that Blue Dot doesn't give me any more velocity out of my 6" barrel, however, it does produce a spectacular flame! I'm talking 'light up the night' size flame even at less than a full loads. In addition, while the Power Pistol gives a roar the Blue Dot is more of a crack. I also use Power Pistol in my 45 Super where a decent load produces 1,307fps pushing a 200grn bullet out of my 6" G21L. All in all, I find that 40s&w, 10mm, and 45 Super do well with Power Pistol without abusing the brass.