definitely disappointed with the battery. I think it has something to do with the processor and it straining on the 1080p. The 720p version should be better, I think. Just look at Xperia Z vs Xperia ZR battery life - same processor, same OS, same battery (essentially), but lower resolution on ZR.
But the fact that the cores on Intel Atom are always running (i.e. full quad core at all times), makes the life worse I think. Overall, a bit let down.
If the Huawei P8 returns a battery life of at least 70 hours, then I'll consider getting it. Otherwise, I may just have to go with a Sony compact...Z3C prices should be coming down quite a bit