I have used stove for 2-3 months now.  I find that sometimes the start button does not take the first try.  I had to adjust my settings to make the over hotter as it was not cooking through to the middle of things.  It was not set at appropriate setting in the factory.  I had to call customer support to figure out how to make over hotter.  Once I got that figured out, my pizza is done in the center!