The other day I was furiously trying to finish something in Scrivener when I had to stop typing for a moment as my baby daughter was heading for the power strip. When I moved the strip out of the way the power to the computer disconnected. When I restarted the computer I discovered I had lost… not a word. 
Fantastic program in general. Dual panes and the floating scratch window by themselves make work so much more efficient.
Thanks!
David