I’ve never owned one. I looked at the SU-16 as a backpack-survival rifle, but when I held it, it just felt too cheap. Most of the newer stuff like the bullpups are illegal here in the people’s republic of kalifornistan.
In my experience, their early designs (.32, .380, 9mm, & 40 cal handguns) were cost effective & relatively trouble-free. I also had no problems with a .40S&W Sub2000 (gen1) & a PLR-16 (pistol version of their SU-16). Based on what I've read, some of their newer stuff (rimfires in particular) might be less reliable, so obviously YMMV - which I believe is also true for any individual firearm from any manufacturer. Having sold most of my guns a while back, I don't have 'a dog in the race' & won't react with outrage if anyone expresses a different opinion (although I reserve the right to laugh at any replies ;>)...