We use our stovetop pressure cooker quite often. We mainly use it for risottos, beans and lentils. Risotto takes 5-7 minutes and beans don't need pre-soaking. Stews and large flavourful cuts take about half their usual time. Smashed new potatoes are also a quick and easy side that can be ready in 10 minutes or less now. For sizes, the smaller size is better for risotto as it will not burn in the time it takes for the steam pressure to build up. However, the taller larger size is better for roasts and making bone broths. An all purpose size would be the middle 3.5 qt size range where you can still make risottos without scorching the bottom and cook smaller cuts of meat.
The advantages of an electric pressure cooker over a stove top one is that the temperature can be easily set and easily controlled. For a regular pressure cooker, you are never really able to walk away from it as the temperature does fluctuate depending on your cooktop. I've also been looking at the Instant Pot too but can't justify getting one since I have a few stove top ones.
I personally don't use crockpots that often as I'm not comfortable leaving something on while I'm away. I use Thermopots instead for that purpose. If I am to be home then I just use my French oven.
Great information. You just about convinced me to get one for quick sides, and then I'd use it for shortcutting tough cut cook times, though I'm not against slow cookers.