Of the 3 items you mentioned, I only have an Instant Pot, but I LOVE it. I can take meats from freezer to table in minutes, for one thing. Tonight I’ll be making beef short ribs. A favorite is to throw a whole chicken in, cook it up, cool, debone, add some homemade mayo and diced celery, and there’s a week’s worth of chicken salad for my lunches.
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No desire for a smoker, personally, as the only meat I like smoked is ham (and to me, everything cooked in a smoker comes out tasting like it should be ham!).
Don’t have the sous vida. I doubt I have the patience for it.
It really comes down to what you are looking to make, as someone else pointed out, and what you think you will get the most use out of.