Hi All, I've been out of the Glock world for about ten years. Went back to 1911, discovered the great BHP and SIGs. Recently I pulled out my old Gen 2 19, Gen 3, 26 & 34 and had a ball. So it's time to get back into Glocks. I'm looking at a 21 with what i guess is sf (short frame??) and of course gen 4 is completely new to me. Are the Gen 4 21 sf good pistols? Anything I should be aware of...problems with gen 4 etc.? I looked at gun brokers and best price was around $575.00...Ok price? Sorry for all the question but I'd like to get it right the first time. Thanks in advance for any help you all can provide. Wanna kill these ads? We can help!