Have I tried turning it off and back on again – yes – but it doesn't turn off or on when it has gone in to black screen mode, no matter how long you hold the power button for, it does nothing. When it does this the only way to kick start it is to try and charge it, then it bursts in to life.
Turning it upside down and shaking it does nothing either – I would like on occasions to try throwing the thing violently at a brick wall to see if that helps but so far have managed to resist!
If it worked as it is supposed to it would be great, but it doesn't. I think I got a friday afternoon one!