Still have a Gen 4 19. Have several mags for it, changed the sights and the slide release. I don't outright love it, but I don't think I'll ever get rid of it, it's just a good workhorse and I certainly don't baby it. If it blew up or someone stole it, or if it got lost in the woods, I wouldn't cry, but I'd probably buy another one. It's been reliable as the day is long, and with the load it likes at 15-20 yards, I can hit all day with it. That kind of gun gives me a good deal of confidence.
I've tried a few other models and like them enough. I did enjoy shooting the 30S.
I'd be in the market for a 20 if I could afford to shoot 10mm.