IMO KelTec products do not lack quality as much as they do finish.Like I said, I have owned Kel-Tec products. I no longer do for various reasons, including a lack of quality in my eyes.
I am sure there are many happy Kel-Tec owners, but I feel that their designs are not fully thought through from an engineering durability and manufacturing standpoint. To be fair, the NAA Guardian is not perfect in my opinion either- just closer to the target.
I have had pretty good luck with their P32, P3AT and SU16C, but did have a problem with the PF9 I owned.
On the other hand the NAA Guardian I owned looked great but was unreliable, too heavy compared to the P32 or P3AT, much more punishing to shoot than either of the KelTecs and did not have nearly as good a trigger as the KelTecs.
There now are a number of other pistols in this size category that are IMO much better than either the NAA or the Keltecs.