I've been using leankernel for a few weeks now - typically I get 3-3.5 days of moderate use on a full charge.
I haven't tried to just watch videos all day to drain the battery quickly though, so YMMV.
LG G2x - Eaglesblood AOSP - sold
Samsung Galaxy S3 - CM10 - sold
Samsung Galaxy Note 3 - rooted, removed bloat, Knox, CIQ - current