My favorite brand is Instant Pot, but I also own a Cuisinart that I like. You can read more about both here.

For a family of up to six people, I recommend at least a 6 quart. For larger families, go with an 8 quart.

The only must-have accessory is extra rings. You won't need them right away, but after a while the rings take on an odor that is impossible to get out. It's also nice to have rings in different colors, so you can keep one color for sweets and another for savory dishes.

The difference between these models is that the 7-in-1 has a yogurt making feature. If you think you'll use that feature, go with the 7-in-1. If you know that's not something you'll use, you can stick with the 6-in-1.