I've owned a FIIK Big Daddy for well over a year now.http://fiikskateboards.com/fiik-electric-skateboards/big-daddy-electric-skateboard.html
It definately has it's place alongside all the other boards I ride. I've got 2 lithium batteries, so when I go for a cruise I get over 30kms range, with speeds of up to 35 kph =) I'm tipping after 30k's of pushing along with a mountainboard, the 'ol legs would be pretty sore, LOL.
Benefit is being able to ride up hills, do mad burnouts, monos and just generally freak people out. Great alternative for commuting round the hood, than using your car. Also heaps of fun on the beach and walking trails. Means I can accompany my girl on her bike, while still being on a board. We've done most of the Warburton Trail together, still got 18k's or so to do for the last bit.
I'll make sure I bring it next time we meet up, so you can have a squirt on it. You will love it!
This is a sped up vid of my and a mate doing the Mullum-Mullum creek trail. It has some paved parts, but mostly gravel and dirt