Approximately 90% of ALL microwaves, regardless of brand name or type, are produced by Goldstar (in Korea) who markets products sold in the United States. Choose American brand names and shop price. Look for higher wattage. Products by Sharp, Norelco, Quasar, Panasonic, Sanyo & Samsung are difficult to obtain parts for. EWave (Home Depot) rated the worst in Consumer Reports. I recommend Whirlpool, Electrolux, Magic Chef, Hotpoint and Kitchenaid.
Microwaves have turned into a disposable appliance due to inexpensive pricing. Built-in, double wall ovens may be the only microwaves worth repairing.