I'm not super impressed with the footage it produces, it can be quite jerky. But it is what it is, if you need some filming and don't have a camera man what other choices do you have?
I think it depends what you expect when you get it, if you are expecting professional level filming or just want to get some video of yourself. I wouldn't mind having one if I felt comfortable leaving my camera unattended on the beach.
I love mine. It takes some playing with to figure out how to best use it. As far as the footage goes that would depend more on your camera than the tripod. I use mine mostly at the cable park. It has no problem tracking around the whole lake. It will lose you when you change direction really quick if it is following you so it is best to be going to and from it more than back and forth across it. The further you are the better it tracks.
I tested it for the first time with a friend in Ilha do Guajiru, Brasil (sea). Oddly enough it got rusty after the first session.. I admit that there was some body dragging involved, but we all whipe, right? The unit broke and would not charge anymore. On the bright side, he got a replacement unit in just a few days even though we live in south america, so good support there.
Btw, the unit only moves sideways, so practically speaking for kitesurfing it is only useful when you have on shore wind, or you have a place where to put the camara in front off or behind you. The thing would need to be integrated with a camera to automatically work the zoom to be useful, imo.
There is another brand that pans vertically as well. Not sure of the name, but I saw it in the kite boarder magazine. It was expensive though. The solo shot is cheap. The other one would be awesome if you had 4 grand to put into a camera and the filming device.