Toaster ovens are awesome. For a toaster oven, there are three key features:
- Big enough to fit the largest item you'll cook.
- Convection, so food cooks quickly and evenly.
- Enameled or stainless/aluminum interior. This lets you use harsh abrasives to keep it clean.
It's a given that your oven should have bake, broil, and roast modes.
For size, you'll probably want it big enough to comfortable fit a 1/4 sheet pan, or a 9" x 12" brownie pan. That will allow you to bake. Much bigger and it will take up a huge amount of counter space and realistically you should use a full oven for the big stuff. Too small and you'll have to fire up the full oven for everything, which defeats the purpose.
Convection makes a huge difference in toaster ovens; because they're so small, they are more prone to uneven heating than normal ovens, and leak heat out the front. If you open them to move food, they'll lose most of the heat, and take a while to get back up to temperature without convection. Convection lets you cook faster and more evenly.
For cleaning and long-term use, you need to be able to scour off the burned-on crap with steel wool or other harsh abrasive. Otherwise the oven will quickly become so unsanitary that it must be replaced, and nonstick finishes never last. The bottom will, of course, be lined with aluminum foil for easy cleanup of drips.
Oh, and rotisserie is a useless gimmick. I've had it on ovens, and never used it yet. Other people may have different experiences with it, of course, but that's my $0.10.
In a small toaster oven, using a pizza stone is likely to be a tradeoff:
- Toasting -- counter-productive, because it will shield the bottom of the bread (or other item) from the direct radiative heat from the bottom elements; you would want to remove the stone for this use.
- Broiling (or as it is called in the British parlance if I understand correctly, grilling) -- Probably not a good idea. In a full sized oven, the stone would be left far enough from the heating elements that it would not be subject to intense radiative heat. In a toaster oven, it might be too close to the elements when the oven is used this way, so might be subject to cracking due to a higher temperature gradient and uneven thermal expansion.
- General baking -- will require a longer a pre-heating period for the oven/stone to come up to temperature, but once at temperature, will provide a buffering effect for more even heating.
- Convenience -- in full sized ovens, people often leave the stone in all of the time, and cook on a different rack if they don't want direct contact with the stone. This may or may not be possible or convenient in a toaster oven, so you may be constantly removing or putting back the stone based on your current use
Note that all of the above is just reasoning based on known facts; I haven't tried a pizza stone in a toaster oven, and wouldn't do so, as they have a generally low thermal mass. I tend to think of them as tools for toasting and reheating, not for primary cooking, baking, or roasting.
Best Answer
A toaster is more efficient than a toaster oven, which in turn is far more efficient than heating an entire conventional oven.
Toaster statistics: Approximate time to make toast – 4 minutes
Watt measured while running – 820 W
Resulting electricity usage – 0.055 kWh
vs
Toaster oven statistics: Approximate time to make toast – 5 minutes
Watt measured while running – 1110 W
Resulting kWh usage – 0.093
Lower kWh usage means the toaster is more efficient than a toaster oven.
Here is the source for the comparison of toaster vs toaster oven.
Now, you can compare the less efficient toaster oven to a conventional oven here (or to a microwave, but you don't really use that for toast). Toaster ovens use about 1/3 to 1/2 the energy of a conventional oven. So if a toaster uses less than a toaster oven, and a toaster oven uses far less than an oven, then clearly a toaster would be far less wasteful than the oven.
So YES, buy a toaster!