Kel-Tec has its fans and detractors.
It appears they had quality control issues up to a few years ago. There seems to have been a significant improvement in the last few years.
Many fans reported great results; others reported issues.
My best example of change is the P17 .22, a very popular pistol. They cannot keep them on store shelves. They go for twice suggested retail.
Preproduction models had real issues. Kel-Tec worked those out, delaying roll-out of production by several months.
I read glowing reviews of production models. The production model pistols simply do not have the problems the pre-production pistols did.