I picked up whichever Panasonic model has the "cyclonic inverter technology" after years of failing to care about reading what makes 1 microwave different from another. I'm pretty satisfied. It doesn't require too much fussing and has an option to turn off the beep.
When my Panasonic died I was not impressed by what was on the market (either crap or the same thing with a more modern look for a ton more money) so I ended up buying my same model for almost nothing on Kijiji, but in the white colour that everybody hated, so it cost me $30, and I replaced the magnetron that failed in my microwave. It's been running like new for years now. The brand new magnetron from the part store was $100, if you're willing to get brand new it will always be cheaper to repair than to replace, but getting the old microwave allowed me to troubleshoot what the problem was (I had no idea what failed until I swapped the parts).