I am on my second KZ. First one 2013 MXT20, had it three years and upgraded to a 2016 MXT2920. Both have been great, no issues on delivery for either (I know my dealer did a great job on pre-delivery inspection and fixed a few minor things as they told me, but I never saw any issues).
The MXT20 had a ramp issue after two years, KZ replaced the rear door/ramp no charge. (we hear all these terrible stories about service, my dealer had me bring it in, they took pics and I went back home. They sent pics to KZ, KZ approved it and shipped a new ramp. When it came in the dealer called me, I took it in the next morning and was back home that afternoon. Great dealer and great service with KZ).
The MXT20 was pre-Thor, the service and my MXT2920 are post-Thor.