Purchased a Solo Shot last month and have been playing around with it for a little while now. It's rather fiddly to try and get it in the right position to lock you in the centre of the screen... but once you get that figured, it seems to work quite well.
Had a couple of sessions of recording waves with no one on them

... until we mastered it. Only downside so far is that the footage has to be taken from a minimum of 200ft away...
Attached is some recent footage taken with the solo shot in action.