The main part, called a "magnetron" which actually produces the microwaves are all made by General Electric. This is the part that usually goes bad so, regardless of which one you buy you are still getting a GE.
All that said, it is really a matter of features. The one feature I cannot stand is a ringing dinging bell that wont stop until you open the door or do something to the thing to make it stop. If you also do not like this feature then do not buy a Samsung.
My last MWO didn't last a year, but I changed the magnatron myself and they dont really cost a lot {$75.00}