I have one, took it to the range 3 times so far. After breaking it in with around 20 rounds I had no problems with jamming or misfeeds. I recommend getting the 1" butt extension, it is easier on the shoulder. It is fun to shoot and best of all mine takes the glock mag's.
The bottom one is my favorite plinker. Both of these are Glock 22 versions. I also have one of the original all metal version (Sub9-40). I would recommend the Glock models because they seem to be the most reliable out of the box. But they all shake out as very reliable after about a 200 round break in. For in depth feedback look into http://www.ktog.org . It's a Kel-tec owners group forum.
I can vouch for how much fun they are to shoot, but I don't have one yet, I shoot 3wbs (the guy above) or one of the other KTOG members when we have one of our annual meets. They nice cheapinexpensive plinkers and just plain fun.