I picked up my Kobo on last Tuesday (May 4) and have been reading ever since. After the required 3-hour plug in, I have only turned my Kobo off twice to demonstrate to friends and family.
Today is Friday (about 4:15) and I have finished approx 1000 page turns.
My battery indicator is still showing 7/8ths full.
As I said, so far so good...
F