I usually like Kel Tec stuff for its innovation, but this thing does not meet my approval. It's great they took a magazine system that's already available in the P90 mags, which at $40 is downright cheap for what it is. It's nice that there's another 5.7x28 option out there, but that's where my praise ends.
I don't see this pistol being a success and I have doubts that it's going to have long term durability. How difficult is it going to be to clear a jam, which with that magazine in this new gun is bound to happen. What makes this more worth owning vs a 10 inch AR pistol w/ brace in a MUCH more common and less expensive caliber that I can run with a 40 rd Magpul mag? What, it's going to weigh a pound or two less? How about the Kel Tec SU16 rifles, specifically the B and C models; the B weighs 4.5 lbs stock and the C has the folding stock and ability to shoot it with the stock folded and both have a full 16 inch barrel. Both of those rifles will cost half or more than half what the P50 does once it's tricked out with a potentially legally questionable brace and optic and when the SU-16C works just like the P50 would with a folding brace, which, let's face it, that's what the P50 is built for, what makes this P50 worth it? Just the P90 mags and the 5.7 cartridge?
Sounds like a range toy for an operator to show off and make others jealous.
Further, the jury is still out on the 5.7x28 as a pistol cartridge. It hasn't exactly taken off and that may be due to lack of affordable guns not made by FN, so we're gonna find out in the next 5-10 years whether the 5.7 is a contender or pretender.
It will be real funny tho over the next few years when more and more manufacturers besides boutique makers, FN, and Federal make a 5.7 factory ammo and cite the "overwhelming demand" for 5.7 guns, all four of them, when they're digging in their heels on making .32 and .327 Magnum ammunition while .32 revolvers are flying off the shelves yet they say there's "no demand."