I carried a Kel-Tec P-11 for about two years. It performed flawlessly and was remarkably accurate.
Some folks can get used to the long, double-action trigger, but I never could.
As I said -- it was(is) accurate, but that was punching paper. When I tried the gun in IDPA competition, I did less well with. (I generally do very well in my class/division when shooting other guns.)
I eventually retired it and then traded it for a small .22 rifle (set up for NRA target shooting. I'm pleased with the trade. I now carry a Star Firestar Plus (about the same size, a litte heavier, but single-action with a much, much better trigger; comparable capacity, just as concealable. The first time I tried the Firestar Plus in an IDPA match, I had the best time. (Small match, no world-class competitors, but still I did much better with it than I did with the Kel-Tec.)
If you can work with the trigger, I think they're hard to beat. But don't fool yourself into thinking that because you "punch paper" well with it, you'll do well in a life/death situation. Try it in a competition environment. While its not nearly as difficult as a real confrontation, you may be surprised... negatively.
(Of course, that said, many of us would probably be surprised if we tried carry weapons in a competition-like situation, where you don't have time to plan, to think, or slowly squeeze that trigger. ... I'll bet a lot of folks carrying a small revolverswould have similar or worse problems.)
The problem with the take-down pin seems to be due to an out-of-spec outsourced part for a part of the past year's production run. Never had that problem with mine, and I put thousands of rounds through it. Kel-Tec seems to have fixed the problem for most owners.