I have been using a Sig 220 for duty and used it during the academy. I bought a Glock 26 for BUG carry and off duty use. I haven't shot a Glock it 2 years and I qualified at night with my 26 the day I bought it. I actually shot better with the 26 than I did with the Sig 220.
I am really starting to love the striker type firing system and the I'm seriously thinking about switching to a Glock for duty use. I love the durability of the finish and how maintanence free it is. Now the question is which one.
1st is a Glock 17. Full size, takes same mags as my 26. It'll limit the calibers I need to stock at home. 3 mags with 2+ extensions gives me 58 rounds of 9mm plus the 12 that are in my 26 (extended mag). Very fast follow up shots that I can still place accurately.
2nd is a Glock 34. Longer sight radius. Higher velocity in the ammo. More accuracy potential over the 17. Same benifits as the 17. Except the 34 would be harder to conceal when carried off duty on accasion.
3rd is a Glock 21SF. Obvious benifit of the 45 caliber. Reduced mag capacity. 40 rounds if mags are left unextended. Extended will bring me up to 46 rounds. I have not handled a Glock 21SF, but I have handled the regular 21. The regular 21's grip is a bit long front to back for my comfort, but the width is fine. And that problem has been addressed by the SF.
The ammo used in 9mm is 147 grain Gold Dots. The 45acp ammo used is 230 grain Gold Dots. Also I really don't like the 40 caliber round which is the other approved caliber. So its limited to the 9 or 45.