My 21 found it's younger brother today -Gen4 17. I became a Glock owner a few weeks ago, and I am kinda Glock crazy now. I cleaned it and took it out shooting today and really like it. I thoght the recoil would be light since the G4 has a double spring and it's only a 9mm, but it was still a little snappy. My groups started really tightening up close the end of my 100 round box so i am sure the spring will lighten up and I will love this thing. They aren't pretty of course, but I love the way they shoot! I have gone from a H&K to Glock it would appear