I carefully researched before purchasing this oven. I received it promptly :) I used it for over a week. Because the inverter technology was new to me,. i thought that i was not using the oven properly., After stuggling, as i said for a week, it became clear to my husband and i that no matter what we did, the oven would cook correctly. It took over five minutes to make tea, when my old microwave oven that was larger and less powerful, lower wattage, only took 90 seconds!