Is it better to heat food at a lower setting for a longer time in a microwave oven?

Or faster at a higher temp setting?

I argue this with my wife. She always uses high setting. I use low and slow.

Like with a leftover, nice, medium rare steak. I slice out thin, lay out the strips in a microwave safe paper tray or paper plate and I set the microwave to level 2 for about 4-5 minutes. She'll set it to High and cook in 2 minutes. Mine comes out warm and still medium rare. Hers will be gray and hot.

Of course,she also does the same cooking eggs on the stove and burns them. Every time.