I havent ride a bike for a decade, but halfbike 2 had attrack my attention on FB years ago. Until the HB3 campaign launched on kickstarter, I think I should go ahead this time. Received the HB3 early Aug, it wasnt as difficult to ride as I thought when I watch the youtube about HB2. Basically provided you've got a wide enough area you can ride it in straight line immediately. Still remembered the first time I ride it my whole body (specially my shoulder) was so sore because I need to keep my body in correct balance. The rear wheel steering is really one of a kind and is very nimble. You can make a U turn in a extreme small diameter; but of course it takes time for you to master the skills. I use it for my training (I hate doing workout in gym), I also like running thus by doing this alternatively I can keep myself busy.
The only thing I can comment about it is that the handle bar is a bit too short, I bought the handle bar extender to further lengthen it by around an inch each side. It would be great if the weight can be reduced too.