Now, could there be a difference between gen 1 with controller on top back that's square and controller on top back that's rounded be gen 2.
Then what would the controller on front be?
or may Masterbuilt have it wrong on their site?
I could be wrong on this, but I think the only difference is, the controllers that are square do not have the internal temperature probe attached inside the smoker, so you can constantly monitor the internal temp of the meat.
I've owned 2 smokers with the square controller and there is no meat thermometer inside the smoker. My buddy just bought one with the rounded controller and his has the meat thermometer. If there are other differences between these two smokers, I am not aware of it.
I would stick with the smokers that have to top mount controllers because they are much easier to replace, should it go bad.
Hope that helped.