Good question. I was considering the 16C folder as it looks light enough to pack when working in the woods. Seems like there aren't many Kel-Tec owners, other than pocket pistols, here, but I too would appreciate any owner's opinions. AND, Hillary hates'em! Another plus. Mac.
I own a kel-tec sub 2000 and love it. It is chambered in 9mm and uses glock mags. I have had it for two years now and it has performed well. At the time I wanted a 9mm rifle to go along with my 9mm Beretta PX4. I did a lot of research and was going to by a Ruger 9mm carbine but the cost was twice that of a Kel-tec sub. I ended up buying the the sub 2000 and I am glad I did. It is very accurate and easy to get on target. I like the Glock version because you can get 33 round factory magazines for between 30 and 40 dollars.
As far as the 16c, I have not shot one but when I was range officer at my gun club one afternoon, I witnessed someone shooting his 16c for the first time. He did not look like he was having much fun and kept complaining that it was uncomfortable. For a few hundred more, i think an Ar-15 would be a better bet for a 223, but, that is just my opinion. I bought my sub 2000 for $318 dollars and I have gotten more than my moneys worth out of it already. It is simple to use and can be folded down into a briefcase. also, you can put a surefire on it or another type of tactical light and still fold it down.