I have a love/hate relationship, even close to a S/M-relationship to my Kadet.
No problem whatsoever with my 9mm 85B, but the Kadet recently started to trouble me. From working good, it has now turned on me, as if being possessed by a hippie-pacifist spirit.
After approx. 2500 rounds of various ammo-brands, I get FTF's (Feed AND Fire-failures), FTE's (Extract AND Eject) combined with several stovepipeing. 3 out of 5 rounds. -Oh, not to forget, on my newest mag, the slide won't lock after the last shot.
I would say, be careful of buying used Kadets, eventough they may sound cheap.