Used to have a .380 Guardian. It's considerably heavier than a Kel-Tec, but also a bit smaller dimensionally.
NAA Guardian:
4.75" x 3.53" x 0.93"
6+1 capacity
18.7 oz. empty
Ruger PCP:
5.16" x 3.6" x 0.82"
6+1 capacity
9.4 oz. empty
Seecamp
4.25" x 3.25" x 0.91"
6+1 capacity
11.45 oz. empty
So the Guardian is about 3/8" shorter, but about double the weight empty. And of course, the Seecamp is even smaller still.
My Guardian was reliable as long as it was kept clean, however, the extractor was a joke. It just plain would not extract anything, let alone hold a round to the breech face. With a round pressed to the breech, there would be about 1/20" of clearance between the extractor hook and the rim. If you got a failure to fire or something, you'd need to point the gun up while racking the slide, and hope gravity pulled it out. If not, you gotta stick something down the barrel.
Also no ejector, it would rely on the next round in the magazine to eject, so the last round would sometimes stovepipe. That's actually intentional, though. The stovepipe jam tells you when the gun's empty.
Still, it was reliable when clean. The extractor was never an issue, but it didn't exactly give me any warm fuzzies.
If I had to do it all over again, I'd save up the extra money for a Seecamp. Twice the price of a Guardian, triple the price of a Kel-Tec, but I'm betting it's worth every penny.