I have an MES 30, an older model. From the various reports here, it seems to do a better job at producing longer smokes at the higher end of the temperature. It has a full size chip box and loader versus the current half size. It does not do as good a job at warm smoking (e.g. 140F).
My biggest gripe with my MES is the failure of the wires connecting to the heating element and the messy job it is to get access to them for repair. Masterbuilt has modified their machines in current models to have an access panel to those connections -- very good move on their part.
I definitely like the ease of operation of the electric models versus propane, wood and charcoal models. I used to have a R2D2 shaped Cajun Smoker that used charcoal and a soaked wood for smoking. It would often burn too hot and/or produce too much smoke. Very hard to control for "low and slow smoking". I have no experience with smokers with an offset fire box, so cannot speak to them. I have had friends tell me that they can do a decent job of maintaining an even temperature with a propane smoker system -- I wonder though. The electric contols can be set and not touched for hours without concern.
I now have an A-Maze-N smoker and have used it for cold smoking of cheese -- I cannot think of any better way to do that. I only wish that the AMNS fit better in my MES30.
I wonder if a small (e.g. computer size) fan would help in a smoker? Some of the guys who have done self-made mods could speak to that. Those who use something like the Smoke Daddy have a fan to force air through it.
Clean up is messy -- but I don't have any good ideas about how the manufacture could improve that. I usually spray surfaces such as the grates and water pan with PAM or similar. That helps cleanup, but it is still a chore.
Good luck to you in your endeavors.