I have OPINIONS haha.
My DH got me the InstaPot after my second, smaller, older crockpot died. I think he was hoping we could therefor get rid of the newer larger crockpot, AND the pressure cooker.
I use a slow cooker FAR more often than I use a pressure cooker (because I want to eat when I get home, not start cooking). The instructions with the InstaPot are extremely detailed on how to use it for pressure cooking, but next to nothing about how to slow cook in it. As far as I can make out, there is ONE setting, which is to slow cook on high for 4 hours and then revert to keep warm. No options for changing the heat or the length of time. Also the insert is smaller. This is fine for making a meal for 2 (since you want it fairly full, although a piece of foil on top of the food also prevents drying out if it's less than 2/3 full). But it is not big enough for the turkey or goose carcass for stock-making, so I am keeping my old one too (it's just stashed in the pantry instead of out on the counter in the appliance garage).
As a pressure cooker... I read through the manual/cookbook once, when I got it, I don't want to reread it every time I cook something. I recall the rough outline of 4 minutes for beef and 6 minutes for chicken once it comes to full pressure. That is nowhere in the instructions that I can find. My chief annoyance is that the pressure-release valve is very finicky: twice I have cooked with it and it never reached pressure because although the valve was on it apparently was not on "right". Which means instead of under 10 minutes the meal takes over 30 to cook, in which case I would do it on the stove top so I can poke it and add stuff!
Oh and I still want my manual pressure cooker because it can't be beat when you are cooking on a boat with one burner and limited stove fuel...