Battery life it depends, Octa performs better at CPU tasks but A15 cores tend to consume a bit more power.
Calls: Qualcomm modem seems more power efficient than the Intel in the G900H.
In general usage, they are both in the same ballpark. For typical tasks the A7s in the G900H consume less power than the Krait, but really intensive tasks like heavy games or benchmarks might consume more battery due to what I mentioned above regarding the A15 cores.
Audio chipset: G900H has a Wolfson chip, which many consider superior to Qualcomms.
and as i saw on the later pages, qualcomm has better dev support right? then can't we flash a rom on both phones? so about game support which one comes in handy?
which one gets hotter? is there any head to toe comparison out there? someone how has both phones