I have a sous vide temperature controller that I connect to my large crock pot. Naturally it won't do pressure cooking, but I use it for a few things that require precise temperature control.
I use it for yogurt. I also like making beans in it because it allows me to cook beans for several hours just below boiling. This allows the beans to cook throughout without falling apart, so the texture and flavor is much better.
One of my favorite things to do with it is make eggs. I cook a dozen eggs in the shell in a water bath at 148F for 90 minutes, then put them back in the refrigerator. The result is egg yolks that are just barely firm and custard like with the whites still a bit runny. In the morning I crack two of them in a small bowl with a little salt and pepper, then microwave it till they are warmed throughout. This finishes cooking the whites. I like to eat them just like that or sometimes I will put them on top of some toasted rye sourdough.
Sous vide isn't tricky. You'll need a decent vacuum sealer. Meats come out cooked perfectly throughout, although naturally it doesn't brown so you need another method for that if you want. A cheap cut like bottom round cut into a steak comes out as tender as filet mignon, with more flavor. The only trick is to make sure there is space between if you use multiple bags, and if you cook at higher water temps, say around 170F or so, whatever air is left in the bag will expand and the bags will try to float, so you need some way to keep them submerged. I use a taco rack in the bottom, with a couple of metal skewers bent to conform to the shape of my crock pot poked through the unsealed portion of the bags.