Except for the fact that these things could cost over 1000$, yep you read right 1000$. The saying goes that "money doesn't grow on tress" and I can verify that claim since I have no money and if I did I wouldn't be in an able position to spend that sort of money on these kinds of luxuries.
Don't forget about the fires as well. Yup fires, and no it's no some feature to keep your feet warm it's an actual malfunction of the device witch leads to fires being created under your feet. These fires are usually caused by faulty ignition switches and usually from low end "hover boards" as well. It's hard to tell witch ones are low end since these companies always buy them cheap and jack up the prices three fold. So the excuse of just buying the more expensive board is out of the picture.
So in conclusion I think that these boards a re a novelty act that will wear off pretty quickly so it wouldn't be wise to invest in one. But if you still really really want one, your best bet would be to buy from the manufacturer directly, so being the good person I am, I have put a video below that tells you a bit about the "hover board" and shows you how to get it cheap.
-Phil