I updated to ermine as soon as I finished unpacking my PE. I have noticed that the automatic hibernate function (close the device up) doesn't work more than about 5% of the time. If I close it and it doesn't hibernate the battery runs down in a matter of 5-6 hours. When the PE is truly in hibernate mode the green led next to the power switch flashes on every 5 seconds or so. If the light is on continuously, the device is not hibernating.

I have to flick the power switch and select the "hibernate" option from the menu in order to get it to hibernate reliably. So far I haven't had any problems with it coming out of hibernation.

I have also had a problem with the device thinking that it is still connected to my computer via USB even when it is not. I find that after ejecting the device via either Calibre or Windoze, then stopping USB storage on the device, then unplugging the USB cable, the status bar still reports a USB connection. I don't know if it takes any extra power or not.