It would really interesting to see the same battery life charts normalized for the display's power draw. I could be totally wrong here but my understanding is that that's an extremely significant factor in a lot of "casual usage" battery life benchmarks. If you take the display into account, then you can start to see how relatively efficient different OS' power management code really is.
Of course, if what you care about is the efficiency of the PM software, looking at total battery life probably isn't the most meaningful factor either, as they all have different-sized batteries, so what's important is power drain as a function of time.
These measurements are both from Anandtech, which a while back absorbed this obvious lesson and started testing at a standard 200 nits, instead of "50%" brightness like a lot of clueless review sites use (including Ars Technica, sigh).
Of course, if what you care about is the efficiency of the PM software, looking at total battery life probably isn't the most meaningful factor either, as they all have different-sized batteries, so what's important is power drain as a function of time.