I've carried and shot my P11 now for 13 years. It has in excess of 11,000 rounds fired, all standard pressure except for 3 or 400 +Ps. It's rated for limited +P use so I limit them and carry them. It is quite accurate, amazingly accurate. I can put 5 rounds into 3.5" off the bench at 25 yards with it and off hand, 6" plates at 25 yards have no chance.
Some say it's not a fun gun to shoot, but I have a blast with it mowing down those falling plates at the range and other practice. It just takes a bit of getting used to.
I've not had the thing jam that I can remember except on some odd 147 grain stuff it didn't like. I reload and mostly shoot my own reloads out of it. My Dillon square deal is in 9x19 as that's what I used to shoot a BUNCH of for IDPA. I've scored well a few times in IDPA with the Kel Tec when I wanted to try it. My scores were a little slower than my P95 I was shooting at the time, but not THAT much. I amazed some of the shooters out there with it who didn't give it a chance in hell. LOL
I shoot the gun well and am very confident with it considering all the shooting I've done with it. KT has great customer service, though I admit I've never had to use it. If this thing ever does need service, I might just buy a new one while I have it off at KT to test the lifetime warranty. I like it that much.
I know nothing of the other guns, but I can recommend the P11. Some don't like the trigger, but I'm an old DA revolver shooter and find the trigger fantastic, long, smooth DA which stages a little. It's very safe to carry and easy to shoot well if you can shoot DA. If you're a 1911 guy, you're going to have to learn the trigger, but revolver shooters will adapt to the longer throw. Any good DA shooter knows smoothness is everything and the P11 trigger is WAY smooth compared to most any revolver DA, well, especially after 11K rounds fired.
The KT P11 is the SAME EXACT SIZE as the PF9, just about a little over 0.1" thicker and 2 ounces heavier.
I carry mine in my strong side pocket just fine and it is a double stack with 12 round factory mags available.