We are a family of two, and while I have two slowcookers I really only use my 6 qt Hamilton Beach Stay Or Go.
My smaller one is an old Rival and it cooks WAY too hot. I have gone through three expensive slowcookers and this gem that I paid $25 for four or five years ago has been the best of them all. Easy to clean, perfect to take chili to a potluck, and it cooks evenly.
I have put only 6 chicken drumsticks on a bed of sliced onions in that thing and had them turn out perfectly, and I've done a 6 lb chuck roast and had it turn out the same way. I honestly don't see the reason for a smaller one, but of course I married a man who loves leftovers too!
~ "The right shoe can change your life...."- Cinderella ~