The Kahr has a lighter feel for those who can't shoot a true DA. They're TOO light for my liking. I prefer a more revolver like feel. I shoot quite well in DA, have a lot of fun with the P11 shooting 6" plates at 25 with it. I can go through 100 rounds no problem and that's how the thing got the round count it has. LOL Mine's the old 10 lb trigger, too, not the newer 8 lb. My Taurus 85UL has a very light DA trigger for a revolver and measures 11 lbs. Most J frames measure 13 lbs. I really don't see the problem with the P11 trigger if you can shoot DA revolvers at all. Of course, many don't take the time to learn that skill. It really ain't that tough, though. I'm quite good to 25 yards shooting DA and I know that I won't ever be that far away in a self defense situation. The long, stiff trigger is safer to carry in pocket carry and I just prefer it. But, I'm one shooter, rather old school, and everyone has different preferences. The 1911 guys will tell you a 4 lb preloaded Glock safe action (which reminds me of Kahr triggers) is a "nasty trigger". It's all relative, I guess.
As to the PF9, the trigger is 7 lbs and it's shorter because, like the Kahr, it's a preloaded trigger, hammer (not striker) is not fully unsprung in battery and it does not have second strike capability. The DA phobic seem to prefer it to the P11. Kel Tec basically used the P11 slide/barrel design with the P3AT trigger design when building the PF9. The bugs seem to be out of it, now. When it was first introduced, like the P3AT, it had some reported problems. It's been out long enough now that if I wanted one, I wouldn't hesitate. KT is a good company with a great customer service department, too.
}, but larger caliber are a wash.) made the difference (at least in the P11's case), but now I think the point you raise is probably the prime factor. 
