My Sharp microwave is over 20 years old and still works fine. It's a crap shoot. A new Sharp might be dead in a year.
I just bought a new Panasonic Inverter micorwave for my motorhome. I love it. Can't say how long it will last though.
I have no idea why they named it "inverter." It does work like no other though. A standard microwave- regardless of heat setting - runs full throttle, off, full throttle, off, etc. This new "Inverter" Panasonic runs steady at any setting. It truly has a variable heat range. Other microwaves do not. I just ran a bunch of amp draw tests on one. At low heat - I ran for 5 minutes and it drew 5 amps steady. I did the same on a new Samsung (not inverter) and at low heat - it drew 14.5 amps, then zero, then 14.5 amps, etc.