I had a G20SF for a few years. I bought it specifically as a "field" or "trail" handgun - to be carried while camping, hiking, dirt biking, etc. I liked how ugly it was, so I'd never have to worry about scratches or exposure to the elements. The big fat polymer frame soaked up recoil very well. It was 100% reliable, and I got pretty good with that nice consistent Glock trigger.
What I didn't like was the polygonal rifling and the somewhat unsupported case area. These 2 things worked against me as a reloader. I didn't want to use inexpensive lead bullets because of the rifling, and I didn't want to load up powerful rounds because the G20 was putting little belly bulges on my fired cases when using hot Buffalo Bore ammo or handloads near the max load data. That worried me, as I'd never seen that before, with any other +P rounds in any other autoloader. I eventually realized that I didn't have enough of an outdoor lifestyle at the time to justify a handgun that had little purpose to me other than being a field sidearm.
I sold it to fund some other firearm purchase, and I haven't really missed it. My new "field" handgun will be the SIG P220 Combat that I just ordered, loaded up with Buffalo Bore 255-grain +P hardcast. I think 10mm is a cool round to have as an option for people like me who shoot semi-autos much faster and more accurately than magnum revolvers. And I thank Glock for keeping the G20 on the market all these years, long before the recent resurgence of 10mm interest and support.
If Glock made the G20 with a 5.5" Ballard-rifled (factory Glock) barrel, a more supportive chamber, Gen 4 texturing and mag release, no finger grooves, and a full FDE factory finish, I would buy one again.