I've had a Gen 4 G17 now for a couple weeks and I find the new design great. The SF frame fits my hand better than ever. I've got smaller hands so the change is significant. The new recoil assembly seems very strong and well-built and it gives the pistol and overall tighter fit-feel. I'm happy that Glock chose to retain the regular vertical slide serrations. I will keep my Gen 3's for sure, however, I will only purchase Gen 4's from now on. I'm really looking forward to the G19/23 versions to roll out! To the Gen 4!