Regular toaster ovens are modest appliances, typically used for not much more than browning a couple of slices of bread, making melba toast, broiling cheese on a pita for an 'instant pizza', or reheating leftovers if you don't happen to have (or want to use) a microwave.
But in recent years a wide selection of convection toaster ovens has come on the market to redefine what a toaster oven is. These ovens offer a number of major advantages over the lowly appliance I used in my first bachelor apartment:
They use convection. Forced air circulation with a fan - to increase the rate of heat exchange between the oven air and what you're baking. This can reduce baking and roasting times by up to half. That leaves less time for heat to escape through the walls of the toaster oven, which means less energy use overall, saving you money. The convection process also results in more evenly browned meats, and better quality baked goods.
They have better controls. Many come with digital temperature controls and timers. Even those with old mechanical controls are better made than the cheap toaster ovens of the past.
They can hold a lot of food. You can't roast that Thanksgiving turkey in a convection toaster oven, but you can fit just about anything else in it. Many will handle a pizza up to 12 inches wide (and in fact some come with their own pizza tray); and some can accommodate up to 6 regular or 9 small slices of bread at once or toasting.
They are great for roasting. Many models come with a rotisserie, and you can roast a chicken, two cornish hens, or a medium-sized tied roast to perfection. You can also cook a regular roast in a small roasting pan. or broil steaks or lamb chops using only the top element.
They are small and inexpensive. Compared to a regular range oven, a convection toaster oven is tiny. But they are bigger than a regular toaster oven and you'll need to allow open counter space for them. Some models cost under 0; the better ones come in around 0-250 (you can get better deals if you watch for specials). If you're tight on space or tight on cash, these appliances are a great way to combine several appliances in one.
You might wonder why you would want a convection toaster oven if you already have both a toaster and a regular oven. If you just want to toast a slice or two of bread, I would stick with your regular toaster; but if you do more than two slices at a time, or you want a lot more flexibility in terms of toasting, roasting, baking, broiling, and so on, it's handy to have a counter-top unit that does all this. And if you're tired of waiting 15 minutes for your range oven to heat up just so you can broil some garlic bread, a convection toaster oven warms very quickly and uses far less electricity for small jobs.
Many people buy a convection toaster oven because the nominal cost over a regular toaster oven isn't that great - and then they wind up using it instead of their regular oven. You can bake casseroles or lasagna in it, roast meats, and bake cakes, pies, muffins, cup cakes, croissants, and cookies. For less than the cost of a service call on your old oven when the heating element dies, you can get a new oven that does it all.
If you're considering buying a convection toaster product I suggest buying the extended warranty option. For an extra few dollars a year it is worth it. While these products are typically solidly built, in this low price range you expect to see some quality issues in a few of the units, and problems in particular with the timers on these units are not unheard of. Fortunately, this common timer problem doesn't prevent the units from working, just from running on timer.
A convection toaster can be great in situations where you don't have the space for a range, or the budget. For example, a small mountain cabin (assuming it is grid connected) is a perfect place for such an appliance. Or if you're remodelling your kitchen and the contractors have gutted it and told you to stay out for weeks at a time, a convection toaster oven in your basement, along with a kettle or coffee maker, will do for most of your cooking needs.
