Lee, I believe your analogy is correct. The disadvantage for me was the size of the grip of the 20SF. I'm discovering that not only are the SF frames a little large, I actually prefer the feel of the Gen4-fullsize pistols--like my new 31G4 and with no additional backstrap added--even more. For me, it's much more the pistol than the caliber.
The 10mm Auto is a VERY powerful cartridge, and if that's what you want to shoot, Glock has pistols for you! <!-- / message --><!-- sig -->
I am interested in the 10mm for hunting, I may wait until the 10 mms come out in G4, in the interim I need to decide whether to get the 20 or 29, I could use the g29 with an extended barrel for hunting, standard barrel otherwise, or just go with the 20
Thank You for the info
Have fun with the 31!