I bought my microwave sometime in 1984, or so.  I thought it was a Panasonic, but now I am not sure.  I remember buying it at J.C. Penney's, and the name on it says "J.C. Penney's", not Panasonic.  It was built in Sept. 1984 (in Japan).

Sometimes, the door has difficulty opening, but other than that, it works great. 

Sorry, I am sure that does not help you decide, but I thought I had to mention how long I've had mine.