While I want a Kel-tec, I do not consider it a "carry gun". A rimfire is a poor choice for defensive use as the priming system is less reliable than centerfire (let the flames begin). While the .22 Mag is a potent round, one I would not like to be shot with, I would not carry one for self defense unless I had no alternatives.
WTS, the FN is probably a better choice, just not one I would make. IMHO trying to make a submachinegun (P-90) act like an assault rifle has limited usefulness as it is not an assault rifle. Then trying to stuff that underpowered rifle round in a pistol where it loses even more velocity and energy, then give the pistol bad ergonomics and a spotty reputation for reliability, add in a price tag that is out of most people's range and warranty service that is second to AMT and you have a real fine offering there.