A couple of days ago I updated my S5 to G900FXXU1ANE2 with Kies 3 from my PC.
I've noticed worse battery life, but I guess its too early to judge so I'll give it a week or so and a few more cycles.
However, I have noticed that during ALL games the battery gets ridiculously hot. I've never had this on any previous firmware updates. If its related to the flash/firmware then I am tempted to go back as it never used to get hot and battery life was a couple of days.
I know there will be some stock answers advising me to do a factory reset, but I'd really rather not.