Some have inverters for continuous power adjusting, others turn on and off the magnetron.

In any case, all that I have ever used have 2 dials, one for power and one for time (and a button to allow to chain multiple time intervals, each with a different power level). I have always used only these 2 dials and I have never used any other buttons that may exist for preset programs.

For many years I have used microwave ovens only for reheating food. Now I consider that I was stupid and I cook all the food that I eat in a microwave oven, from raw ingredients.

This is much better than by traditional means, because it is much faster and perfectly reproducible. Moreover, cooking in a microwave oven removes the need for continuous or periodic stirring that is required in many traditional cooking methods, because the microwave-cooked food is homogeneous (without lumps etc.) even with no stirring, if the time and power level are chosen correctly.