I have an electric CharBroil Vertical smoker. It was free.
Mine does have the temperature controller, like an electric griddle. It is marked from Low to High. The temp. controller works better than the ones that are always on.
To generate smoke, you put either a wood chunk or chips wrapped in aluminium foil with holes in it between 2 lengths of the heating coil. Works ok. I am working on some modifications to make the above mentioned AMNPS work correctly.
It will hold 1 Pork butt on each of the 2 racks. Larger briskets would have to be cut to fit inside of the smoker.
People who own the electronic controls of the MES smokers rave about them.
My Brother in-law has the smaller Green Mountain Pellet Grill which is basically electric. He really likes it. I bought him the tubular version of the AMNPS that is supposed to be able to smoke in the low oxygen environment in pellet grills. I haven't heard how it has worked for him. The AMNTS won't generate smoke for as long as the AMNPS in a regular smoker. It would need refreshed more often, but it should work in that grill. Those are expensive grills, well above the $300 limit, but their owners rave about them. You may be able to get Todd from Amazen Products to make you a longer tube smoker, or weld 2 together. His customer service it outstanding.
If I had to replace my grill & smoker at the same time, I would seriously consider one of them.