I own and love my Glock 20, not at 1st, but now as I have started building my own loads, it gets better and better, I also owned a S&W 610, shot like a laser from day 1, only problem, so does my model 57 revolver .41 mag, to me, the enchantment with the 10mm, is 15 rounds or more, the old saying, one gun, or one handgun, the Glock 20 is hard to beat, accurate enough to headshoot small game, flat enough trajectory to keep someones head down at 100 yards easy, 2 guns, then the 20 may not be my choice at all. I really like the idea of a 10mm upper for my AR. I really think the 10 shines with handloads.