[jlg432]

I guess it depends on how many books you have on your reader and if you have just added some recently.

I get free books from Amazon due to a free daily mailing list that I receive. As I can't read faster than they come I now have over 3500 books on my 8 gig micro sdhc card.

Coming out of sleep is fast and as it is a Glo the only button is the power switch.
Coming out of Power off though is much slower and if I have added any new books or even removed/re-inserted the SDHC card while the reader is powered up a media scan will take place to verify the database. Also editing an existing shelf takes much longer. The exception is adding books to shelves from the Library is faster providing there are not many (4 step process). These are the circumstances that I find adds to my power drain. If I don't play with search, shelf updates or adding more books, the power drain is very acceptable.

I should note that the power drain is noticeable when I do file management work but not extreme as to force an immediate re-charging of the battery.

To summarize - In my case Sleep is easy on the battery than a power off - unless I am putting it away for an extended period of time (which is rare).