The regular, 6 qt. Instant Pot is still on sale for $70, and honestly, it’s probably the one you should buy at that price. But if you need a larger model for a bigger family, or care about aesthetics and a few extra features, the Instant Pot Ultra just went on sale too, in two different sizes.
The 6 qt. model is down to $99, and the 8 qt. version will cost $20 more, both of which are all-time low prices. The Ultra has a few extra cooking modes, but you’ll never use them. The differences that matter are the UI—the information-rich blue screen tells you a lot more than the DUO’s—and the fact that the pressure valve automatically closes when you close the lid, so you don’t have to worry about forgetting that crucial step. If you care about aesthetics, I think the Ultra looks like something Cuisinart or KitchenAid might make, whereas the DUO looks like something you might find at a flea market.
The actual cooking results between the two models should be identical, the Ultra just has a few quality of life improvements that may or may not be worth paying a bit extra for. It’s up to you, the only bad decision is to not buy an Instant Pot.