My sister has a Great Pyrenees dog and yes they're very good affectionate and loving dogs and do make good family pets.
My sister lives in the country in a rural area and the dog has plenty of space to run and play without having to be inside a fence which makes him more happy.
He runs and plays with my sisters kids as well and is very fun.
As long as you have a large enough yard or space for the Great Pyrenees dog then I would highly recommend them as a good family dog.
They require more food than other dogs as well and cost a bit more to groom if you have them professionally groomed.