I flashed last night with no issues. This morning when I powered up the machine kept locking up and eventually rebooting. Something about surfing and streaming radio was causing issues. I reflashed and everything is OK again. If you keep crashing you may want to try a reflash.
I have the '-' key on the num pad and I'm using the US keyboard.
If you view your keyboard settings (bottom left -> Tools -> Settings -> 1st language) the default is English (UK). If you change that to English (USA) the dash will change to a plus sign. This setting seems to be independent of the locale setting which I have set to US.
By design the tablet turns off when the cover is installed. It prevents the tablet from powering on accidentally when it's in standby. Like choover said it would sound like poo...poo is never good.
I had to flash several times before I could get the browser to work. It would say it was starting but it would never launch.
Also, I had several music videos that I had converted to full screen Nokia 770 format and they are no longer full screen. Can someone else confirm that change?
Overall, the 770 seems much more stable. I am finally able to run email, browser, and streaming audio sessions all at once.