With regards the battery, it does last up to 8 hours or so, but you have to close completely when you don't use it, because there's no standby mode, and it takes time (1 min. I think) to start up. It's just not as practical as it could be. I think you (or your friend
) should ask about this in the iRex devices forum, and perhaps looks in the older threads there. This and the functionality of the annotation feature has been discussed there. It's a quite common question.