Several years back (and things may have changed) Panasonic had a patent on the inverter and was the only microwave that offered it. I purchased a Panasonic for that reason and love it.
This from their website:
The Panasonic Microwave Ovens powered with patented Inverter Technology™ deliver evenly cooked meals, from edges to center, every time.
This from their website: The Panasonic Microwave Ovens powered with patented Inverter Technology™ deliver evenly cooked meals, from edges to center, every time.