I thought I was getting much worse battery life on my new MBP compared to my old one, but then I paid attention to screen brightness - when I level match the screens to the same level of brightness, I get the same battery life as my older one.
I'm used to just jamming the screen to 100% brightness, so I've had to get used to keep it around 70% or so.
For max long term comfort, your display should be no brighter than the ambient light levels. Otherwise--if the display is way brighter--your pupils will have to contract when you look at the screen, and dilate when you look away. Your pupils are controlled by muscles and like any muscles, they can get tired.
I have a 2012 MacBook Air and I rarely have the brightness over 50% indoors. And the new MacBook Pros have way brighter screens.
Sitting in my living room right now, my iPhone is at about 15% brightness.
http://www.splasm.com/brightnesscontrol/index.html
It works as long as I disable flux.