Don't have a hoverboard but I do have an electric unicycle (they're usually made at the same factories). It's fast and I use it instead of my bicycle when it isn't raining.
Considered, but I won't have place in my luggage to take it back :(. I did get the chance to ride on them though, they are great.
Shenzhen is an interesting place. I learned as much about China as about the West here - in particular, I wasn't up to date with all the stupid USB-powered shit Westerners buy. Took a few hours of strolling around the electronics market and now I feel like I'm a walking gadget catalog.