I use greenify + donation package (but no xposed) on my phone, as I have a lot of apps I like to use on the F3. I'm not constantly on my phone... use around 25-60% during a typical 16 hour day. (The 60% end includes gaming and streaming video via chromecast.) I top up, but not more than twice a day (aside from bedtime charging). If I didn't have greenify, I'd probably go through 70% or more. I also have the built in power saver turned on, to kick in at 20%.
Anyway... any devs working on this phone have any idea as to when KitKat is coming to this phone? I've noticed some phones out there lately that have similar specs to this phone running KK.