Yes, I said it in the title of my blog: Nokia Lumia 920 hangups fixed in Windows 10 Mobile Insider Preview! or was it accidental?
The thing is since the update of Windows Phone 8.1 I started to get intermittent hangups. I thought the hangups was all software issue but it turns out the OS works fine and the camera using the dedicated camera button but the screen doesn't so I suspect a hardware issue.