That depends on the food.. They are far better at cooking, fish, vegetables and xmas puds than a "real" oven.
Does it have a built in fridge to stop the stuff going off while it sits there? I always thought a combined fridge-microwave was a good idea.. maybe I should hack a £25 Tesco microwave and put a peltier cooler in it? I could put a B&O badge on it and make a fortune. ;-)
Nit picking that should be the faster it heats. The power level doesn't determine how fast it cooks for many foods. Just how fast it overcooks.
But it doesn't make any difference over switching it on and off unless you are cooking very small portions.
Cheap thing then. Mine has a fan oven that works just like a "real" one. I guess you get more if you spend £80 on a microwave.