Well, I got my opus for a bit more then a week now, and I finally really started using it (I had paperbacks to finish first). I got 4 crashes yesterday. Mostly the power + page back worked, but 1 of the 4 crashes was a bit more annoying. The power + page back for 10 seconds didn't reset it. I opened it and tried the inside reset button with no luck either. I was gonna try to remove the battery, but it doesn't seem easy to do either. Finally I just closed it and retried the power + page back and it worked.
I was reading an html file when it crashed and it didn't happen before I was a 3/5th of my book.
Is there any pattern, are some format more susceptible to crash? If I can find a format that doesn't crash my opus I will just convert everything to that format... But well I suppose it isn't so easy