I haven't posted here in a long time, just wasting time today.
I don't know if masterbuilt improved the technology but for the years that I've had the machines, I've always found them to be ineffective. Sometime it worked, sometime it didn't. I had so many problems with the unit, that masterbuilt sent me a free replacement. For the past couple of years, both are sitting in my backyard. The problems that I remember were: (i) They unit kept displaying error codes. (ii) It would give off false temperature readings when I used my ET-732. (iii) Several times, it would shut off in the middle of a cook. Basically, the masterbuilt is just an outdoors electric oven.
Yes, masterbuilt has great customer service because they're fully aware that there are issues with their machines.
I now only use them for simple things, grilling corn, smoking cheese, etc.