I got the 4 out of curiousity. It's my first Kershaw and only assisted opener.
Surprised by how slow the assisted flipper action feels compared to thumb or finger-flicking some of my Spydies. I sort of dislike the handle space the flipper tab takes up when open. The jimping on it is also a bit more aggressive than I'd prefer.
Relatively minor, but it does set your grip back a little and isn't super comfortable. May be part of the reason I haven't been big into flippers in general, the only other one I've tried was the Buck Vantage back when I first started taking an interest in knives years ago.
I also found the lock bar to be pretty slick and not super easy to disengage without your thumb slipping off. There is some jimping there, but it appears to be rounded off and with the coating on top it doesn't add much purchase.
On the plus side, the blade shape is very nice, as is the contouring on the scales. No issues noted fit and finish-wise, lock-up is good, blade centered, no play out of the box. Nice aesthetics overall, I even like the red standoffs. Pretty solid budget option from my initial impressions.
Hard to see myself actually carrying it though. As a lefty I generally avoid righty frame/liner locks. More just wanted to see what it's about and plan to give it to my boy.