I have a G20 Gen 3 SF. 10mm is great. very wide range of factory ammo loads and weights and if you reload you are good to go, you can't get bored reloading for 10mm. If you are going to reload get some extra springs and guide rod's to match your loads. I have the Delta Elite, and Sig 220 Camo as well. I am a 1911 guy and the Sig is a fine piece of engineering but the Glock wins in all areas of importants when it comes to 10mm. The G20 has become my goto firearm. I am looking into getting another just to have in case something happens to mine...? I will probably get the Gen4, I think Glock 10mm is the best bang for the buck. If you want to shoot hardcast get an aftermarket barrel, I have a few, I like the Lone Wolf 6". You can also get a barrel for .40 and few other calibers if you are looking for scalability? If you are a target shooter looking for the best tightest groups or competition, look at the Glock 40.
Opening a can of worms, you could shoot .40 S&W as is, I have shot hundreds through mine.....but I didn't say that, don't tell anyone......Shooooosh!