Is the 21.13-quart capacity big enough for a family?

Yes. At 21.13 quarts it holds far more than a basket air fryer, enough for a sheet-pan dinner or several servings at once. It is oversized for one or two people cooking small portions.

How does it compare with a basket air fryer?

It offers much more cooking area and oven-style racks, so you can roast and bake as well as air fry. A basket fryer is smaller and usually quicker to heat for single servings.

Does 1800 watts mean it needs a special outlet?

No. 1800 watts runs on a standard US 120V kitchen circuit, but it draws close to the limit of a 15-amp circuit. Avoid running it on the same circuit as another high-power appliance.

What should I check before buying?

Confirm the exterior dimensions fit your counter under the cabinets and that the wattage suits your kitchen circuit. Check what racks and accessories come in the box, since large ovens vary.