I had the Note 4 briefly and the Note definitely has better battery life. Not by a mile but definitely better
Im waiting on my S6 Edge but, before the lollipop update I could easily get 2 days out of my Note 4. Since the update I can really only do one. I am not a heavy user by any means. Before update Id go to bed with 70ish percent left. After update 50ish sometimes less. So for what its worth it might not be the S6 giving poor life but the OS.
Cache and reset was done. Still worse battery life and still Android OS, Cell standby Google Services and Android system all far outweigh on screen time.