One of the best pies that I make uses instant pudding mix and dream whip packets. I've made the same thing with a homemade cooked pudding and real whipped cream and, while it's good, the one using the processed store-bought packets tastes better, has a better texture, and holds up better. And it's a whole lot easier to make.
And while I love home made whipping cream using heavy cream, powdered sugar, a little vanilla and a little almond extract, I actually like Cool Whip as well. I think it's got a good flavor and texture, and it is a whole lot more stable - especially if you have some pies sitting out on a table for a few hours Thanksgiving afternoon.