The manufacturer/seller commonly games the reviews so even new products tend to have a few glowing reviews right off the bat.
And if you use the scale that if a manufacturer produces one bad microwave that all their microwaves are bad, I suggest cooking over a fire as no manufacturer is going to meet your judgement scale.
I know I'm five-gajillion comments in, so this is like spitting in the ocean: call a local repair place (unaffiliated) and ask them what to get. The local fridge/appliance repair (group) -- any of the five of them -- will happily chat for an hour about any major appliance in your house. They'll also gossip like fishmongers about who's good at what services, etc.
In general, for very large appliances (large fridges; double-stoves; double ovens) you can just ask them to keep an eye out at the local restaurant auctions. My house came with a 48" prosumer fridge. When my fridge died I got a 10-year-old exact replica from a warehouse for 3500$, rather than 18000$. It's worked flawlessly for 8 years, now.
I just wrote a couple commments here talking about actually talking to people. It's how I still prefer to buy many things.
Reviews? Have pretty much ignored them for many things. It has been hard to see the value, frankly. There are always a lot of them, and the information quality has been high noise and dubious in many cases.
And if you use the scale that if a manufacturer produces one bad microwave that all their microwaves are bad, I suggest cooking over a fire as no manufacturer is going to meet your judgement scale.