I'm a bit of rootbeer float snob, having spent a large portion of my formative years sucking down floats at the Red Steer restaurant at Woodside Plaza in Redwood City. I require a frosty mug, decent rootbeer and scoops (NO SOFTSERVE!) of vanilla ice cream so cold that a tasty layer of rootbeer forms a frozen shell around the ice cream.
But I'm open to variations. I just had a very good float at Mike's Cafe at the Ladera Shopper, despite the fact that it used Barq's rootbeer, that featured vanilla bean gelato.
The upside? Gelato is so much better than regular ice cream.
The downside? Gelato is denser and has to be scooped at a higher temperature than ice cream, thus no frozen rootbeer shell.
Konditorei also has a great variation: the rootbeer float milkshake. I don't condone eating on the run, but sometimes, you just don't have two hands to dedicate to proper enjoyment of a float. When that's the case, the rootbeer float milkshake is an ingenius innovation.