I was wondering if there are any issues with the Glock 21 gen 4's? I just bought a Glock 21 gen 4 on the advice of a Glock armor and then I started hearing more about the gen 4 problems in the G19 and others. I would like to get a Glock 17 also, mainly so I can shoot cheaper with the G17 and then transition pretty easy to the G21. I think I might buy the G17 gen 3 just to be safe. I still have the H&K USP 45 but I want to go with a weapon that doesn't have a thumb safety and one with cheaper magazines. Any help/advice would be appreciated.