Maytag over the range microwave

We purchased this microwave (ymmv4203dw0) when remodelling the kitchen a few years ago. It was not cheap. It's been nothing but trouble almost from the start. Automatic setting for popcorn stopped working ages ago, frequent loud hum that only stops when door is left open, sometimes for more than a day, and now it only heats when the vent is turned on!! Very bad experience and not inexpensive or easy to replace but I guess we'll have to bite the bullet as I'm getting concerned that it may turn on by itself and overheat. I see lots of similar online reviews on other similar models. Shame on you Maytag. I used to associate quality with the Maytag brand. I am soooo over you.