Izzy's, Sebastian Joe's, Dairy Queen, and more: Who makes the best root beer float?

The winner: Izzy's root beer float won us over by using premium root beer, giving us a choice of ice cream flavors, and for easily feeding two people. Sebastian Joe's would probably allow ice cream substitutions, but its root beer was an afterthought, and the portion was petite compared to Izzy's. We liked the nostalgia of going to Dairy Queen and the people-watching at Lake Harriet, but the floats weren't great.