There continues to be concern about the Kel-Tec PMR-30... but it's been out several years now, and after some early teething problems -- they changed the barrel -- it's been well received, reviewed, and generally loved.
I picked one up not too long ago and can only say, "Wow!"
Most PMR-30 users recommend not loading the 30-round mag all the way -- they say it runs utterly reliably with 25 rounds in the mag. I've done mine both ways, without problems. (A rimmed case in a double-stack, hi-cap mag is a real technical challenge, and Kel-Tec seems to have been the only firm to do it successfully.)
Keep in mind this is a short-barreled gun, and you should buy .22 WMR rounds designed for handguns -- a lot (most) of .22 WMR ammo is intended for a rifle barrel, and some of that powder won't get used in a shorter barrel.
My PMR-30 is light, virtually no recoil, has been very reliable, shoots like a LASER and puts on a tremendous sound and light show -- sort of like a CZ-52.
(I wonder if Ruger will try to copy THIS design, too?)