I've had the Instant Pot for only a week, and I think it'll be good once I can figure out the proportions and settings that work for me. But I have to say there's a long learning curve, especially if you're picky about your food texture. Some of my Instant Pot "failures" so far:
1. Mac & cheese. I followed an online recipe, but I rarely cook a whole box of pasta. I dumped in what was left in the box and estimated the amount of water. After cooking, the macaroni was cooked all the way through, but it was sitting in a macaroni soup, so I had to drain it anyway. The noodles were too done for me: I like al dente pasta. And this was with quick release, so I'm going to try less cooking time. Also, the sautee function only has low / med / high; there's no fine control like on a stove. My toddler was distracting me, and I scalded the whole thing on medium. The cheese sauce started to separate out/curdle, and the pot was really hard to clean out afterwards. My husband & toddler were happy eating the results anyway; I guess I'm picky.
2. I cooked dried beans for a chili, and after cooking according to the instructions, the beans were cooked all the way through, but I found the skins kind of tough compared to starting from canned. This is with presoaking overnight. Again, this texture difference didn't bother my husband.
3. Tried warming leftovers in a pyrex dish with a glass lid on. Online instructions recommend 5 minutes on high pressure, but I found my leftovers only lukewarm afterwards. Pot-in-pot pressure cooking, apparently, is sensitive to the amount of water you have on the bottom of the pot (affects how long it takes to come to pressure, and different sources say either 1 or 2 cups minimum is safe) and the container you use (glass takes notoriously long to heat). So cooking times depend on your exact setup.
I think the Instant Pot would be good for long-cooking recipes with forgiving cooking times and people who aren't very picky about the texture of their food. For boiled eggs, for instance, I like the centers just a bit soft. I know to cook my grade A large eggs in rapidly boiling water on the stove for exactly 9:30 and put them in a cold bath. Despite instructions available online, I'm still going to have to figure out what works for me in the Instant Pot. If you like hard, hard-boiled eggs, or you don't care, you can just do a longer cooking time & it won't matter.