I won't comment on the advisability on using a pistol caliber carbine generally for HD. Seems to me that if you are comfortable with it why not.
As for the sub 2k specifically, I've owned one for a while and find it to be a total piece of garbage. Cheaply made and completely unreliable with repeated stove pipes and failures to extract, even after 2 trips back to the factory. You'll hear people say that it is finicky with ammo and that may be true, or it may be the way the mag seats in the newer model, or it may be sensitive to "limp shouldering" -- not having the stock not firmly planted in the shoulder resulting in failure of the gun to cycle properly. Whatever the issue is, which neither I nor customer service at Kel Tec were able to figure out, I would never stake my life on it if I had any other alternative. Period.
It really is a shame, because it is a great concept. Just very poorly executed.