The Bushmaster and first PLR required a little break in.
I believe most of the trouble I had with the AR and first PLR (which was very little) was caused by using Wolf ammo and a couple new magazines that were rubbing on the bottom of the bolt carrier.
I didn't use Wolf in the second PLR and it was totally reliable right out of the box. (Kel Tec says not to use Wolf in any Kel Tec guns)
I no longer use Wolf and all three guns are reliable.
Now if I have a jam it's caused by the brass I've reloaded too many times or a bad magazine.
I'm not knocking the Bushmaster but the Kel Tec has it beat in almost every way.
The KT costs about half as much.
The barrel is 2 inches longer so the muzzle velocity is greater. WWB is 2296fps in BM and 2514 in the PLR.
The PLR is very accurate. I haven't shot the BM at 100 yards much but it doesn't seem as accurate.
The BM uses the AR gas operating system, very dirty.
The PLR uses IMO a excellent modified AK type piston and AR type bolt. The action and bolt stays clean.
Accessories like slings and muzzle brakes/flash hiders are easy to attach to the PLR.
Personally I like the plastic material the PLR is built with better than the Carbon fiber material.
IMO the PLR is a good looking gun and I call my Bushmaster my "Paint Ball Gun".
(I still like the BM but I wouldn't buy another one)
Kel Tec has a lifetime warranty on their guns and they stand behind it.