The size of the Crock Pot is enough for a family of 4 people. The packaging says that it is for 4+, but I think it will not fit more than 4 servings. 
Depends on the dish being prepared. It is made well, there are no instructions for use as such. And there is no point in it, because the interface is very simple and even a child can figure it out. You can increase or decrease the heating level and that's it. The lid holds perfectly, you can easily take the prepared dish with you on the road and nothing will spill. 
The only thing I did not really like was the long heating. We prepared a sauce with meatballs and after an hour it was slightly warm. How long does it take for it to become hot, clearly more time. But otherwise, it is a good thing for the kitchen. 
It can be washed quickly and easily with a regular dish sponge. But the manufacturer claims that it can also be washed in a dishwasher.