Our toaster oven is constantly in use. I use it of almost anything that will go in an oven--in smaller portions.
But if you want a nice crisp crust on left over pizza, microwave it for about 1/2 the time needed to get it hot. Then put it in a frying pan over low heat, cover and leave for about 5 minutes. The toppings get hot, the crust gets crisped up, and the lid keeps everything from drying out.