A colleague of mine did get one for the tube strike the other week. Took him about 1.5 hours to commute about 4 miles on it that day, partly because he was unfamiliar with it, and partly because there only rough potholed cycle lanes for some of the way where it was safer to get off and carry it.

Had a go on it myself. Found it a little tricky getting on, given that you have to put one foot first and it has a tendency to start moving when you take the other foot off the ground. I was wondering if there was a way to tether it to an app with a big stop button you'd keep pressed until both feet were on (although not sure how feasible that would be if the balancing thing requires forward or backward motion).