There’s this thread. It works well on flat, smooth terrain but is so highly geared (and cranks are limited to 125mm) it’s difficult to pedal with any kind of elevation gain. I still have it and ride it occasionally. I would ride it more if I had a good place to ride it.
I wouldn’t think it would be good for freewheel kiting (compared to a regular freewheel hub) because even small feet adjustments would translate into big wheel changes. I’ve looking into kiting but I don’t have a good place to ride. If you have a place to ride and already have the kite skills you’re most of the way there! I personally feel a peg unicycle would be better for using with a kite but a freewheel unicycle may be more practical.