elcreative, the 505 goes into sleep mode after no activity for 60mins, but not into shutdown. I've re-read the PDF manual for the 505; shutdown has to be deliberately performed.
Sometimes, like during Nano, I barely use my reader for days or weeks; when I switch it on after this period, the battery has drained by at least two bars.
On return from shutdown, do I have to wait for the "reader is starting up" malarky? I hate doing this, especially as it often deletes bookmarks etc.
As far as the 350 and 650 are concerned, I still think that the 505 is the supreme ruler of the Sony range