I think you see the Ruger compared more with the Kel-tec because they are more similar designs. They are both very small, very lightweight, polymer pocket pistols (heck, they even look the same). The NAA Guardians are a tad bigger, and comparatively much heavier (the .32 is about the weight of an aluminum .38spl snub).
That said, if you are considering one, the NAA is a good gun. Mine is reliable so far (though I take a bit of a gamble saying that as I don't really shoot it enough to have many rounds through it). They do feel pretty solid (they better at that weight, a bit heavy for pocket guns). On the other hand, the trigger is very heavy and the sights are terrible. They are definitely more money than either the Ruger or the Kel-tec.
I'm going to be selling mine. I'll either stick with my S&W 442 as my pocket gun around the house and when traveling in a carry state or I'll get a more powerful, similar size and weight, Kahr PM9.