I'm 11 full days in, 24.75 hours of reading on lowest lighting level, and now at 51%.
If the 51% is anywhere accurate, then around fifty hours of reading with the lighting on low seems pretty good to me. Especially considering the original numbers set forth in the specs were for more like 30 minutes a day for a month with light on or off, or at total of 15 hours reading time. Now, how they arrived at the idea of 15 hours with or without lighting remains a mystery to me. Perhaps, they were overly conservative, perhaps they intended a higher lighting level, perhaps I'm seeing minimal effects of self discharge so far -though lithium doesn't lose a lot through self discharge.
At any rate, if this discharge continues at about the same rate I think there will be nothing much to complain about with a properly working unit.