Only used it a couple of times but very happy with it so far. Video quality is very good in decent light and far from terrible in low light. It comes with a ton of accessories and spare batteries are cheap as chips too.
From my limited experience it's probably as close as you'll get to official Go Pro quality at less than a third of the price.
Just be wary as there as some fakes floating around on Ebay, better paying a few quid extra to ensure you're getting a legit unit.
Anyway, well chuffed with mine and wouldn't hesitate to recommend it to someone who wants to shoot some action video on a budget. I'll try and see if I can upload some sample video when I get a moment.
I have one, its as good as the old go-pro i have used. The little screen makes all the difference although i think up to date go pros have them now too? I need to use mine more! I took it to the cattas but didnt get it out when it mattered like usual!