So, it's been a long road, but I'm finally here. I'll spare you folks most of the details but I was originally looking at a Beretta PX4 Storm in either .40 or .45. Doing research informed me to the 10mm, the parent of the .40. Lo and behold, Glock has a 10mm (one of the few and extremely highly rated) in both fullsize and subcompact. The problem I'm running into is deciding which one, the 20 or 29 and the sf or normal ones. According to Glock's website, there are 6 choices. Glock 20 Glock 20 Gen 4 Glock 20 SF Glock 29 Glock 29 Gen 4 Glock 29 SF I'm just confused - are the SF versions not Gen 4 versions? Is there any reason I'd want a Gen 4 over a non-Gen 4 version? I used to own an HK45 and was extremely comfortable shooting it - how does it compare size-wise to the Glock 20? I think I've decided on the Glock 29 (this will be my first Glock), just... not sure what all it means. Thanks!