Countertop Microwave Ovens
These are the most common and most affordable type. As the name implies, they sit on a counter or microwave stand. Countertop microwave ovens offer the widest range of sizes, from under 1 cubic foot to 2 cubic feet or more. Even the cheapest of these come with a good array of features: Instant cook buttons, popcorn and potato presets, and auto-defrost and reheat modes. More expensive models have high-end sensors that can perfectly, and quickly, cook a potato or thaw a hunk of meat without cooking any part of it. Convection Microwaves
While these are much less common than simple microwaves, they offer two-in-one convenience that busy cooks appreciate. A convection features allows you to use a microwave like a small oven -- you can roast and bake. The best microwave/convection oven combination browns well, bakes evenly, and puts a nice crust on burgers or roasts. While a lot of people say convection is unnecessary in a microwave, or that it's something they use rarely, plenty of cooks love having it because they don't have to use their big oven for a small job, and they have an extra cooking appliance available for parties and holidays.Built-In Microwaves
The word "built-in" is tossed rather freely around the microwave world to denote any type of microwave that doesn't sit on your counter. Over-the-range microwaves are in the built-in category, as are any countertop microwaves that can be built in, either as a custom set-up or over an oven or range using an optional trim kit. Drawer microwaves are installed lower in the kitchen, below the countertop, and they open like a drawer. They're often installed in kitchen islands or underneath wall ovens. Professional reviews of drawer microwaves are hard to find, however, and user reviews are limited and somewhat mixed -- especially when it comes to durability.