My uncle and cousin each got one for Christmas and I got to try their hoverboards (or smart scooters, motion scooter, handless Segways, etc) out on Christmas day...
They are so much fun to ride and it only takes a few minutes to figure out how to stay balanced on them and ride them around. My 7 year old daughters loved riding them and were riding like pros after only a minute or two... now are begging for one for their upcoming birthday... not a chance though! Too pricey.
Too many issues with them breaking and starting fires right now though. Might wait a year or two before getting myself one. Not too practical, but just fun to ride.