Well... That was fun! Just got back from my inaugural ride, and I'm fully sold on this robot wheel thing.
I dragged my wife along to a nice park and fooled around in the grass until I got my head around the necessary movements; I think learning on grass helped me pick it up relatively quickly because you're forced to deal with uneven surfaces right from the get-go, and falling is less intimidating than on pavement. Once I learned to trust the thing it felt pretty natural, although I'm gonna need to strengthen all those foot muscles I wasn't aware existed... I ended up feeling comfortable enough to ride it back home through a few quiet neighborhoods, and I might try commuting to work soon.