I wonder if mine was a lemon. It had multiple ftf's and left bruises on everyone who shot it. I still think the ergonomics and factory iron's are terrible, I was able to over look that because of how easy it could break down for a camp rifle. I got rid of it because of the the ftf's and the shotgun like recoil, maybe those were problems that could have been solved sending it back to keltec tho? It was a glock17 gen 2 that I bought new in summer of 17.
I have had zero issues with my Gen2 Sub2000 after roughly 300 rnds. Mine is the 9mm M&P version. The length of pull is a little short for me but I am willing to deal with it since the carbine is so light and compact. At 16 inches folded you can keep it in a small backpack and it deploys quickly. I am a average shot at best and can easily hit 10-12 inch plates at 100yrds. I also consider myself some what recoil sensitive and have no issue with the kel-tec recoil. My wife has also shot the carbine with no complaints. With the 16 inch barrel it also is not very loud which would be a benefit indoors.