I am a heavy user* and from my experience BB Passport and Droid Turbo have great battery life. They're in a league of their own, even on a heavy day i still get home with 15+% left.
Sony Z3 and Z3c and Samsung Note 4 are good too. They're ok most of the time, but they are dead at the end of a really long day.
I haven't tested the LG G4 enough, but i think it's comparable to the Sonys.
6 Plus has the best standby, but once you use it it's not not that great. Plus it's the most expensive one and with the 6s plus around the corner i wouldn't buy it.
iPhone 6 and S6 edge are terrible, i never make it through the day.
Of course YMMV.
* what i mean by a heavy user:
4 email accounts with push, i receive ~300 emails per day and i send ~70.
lots of messaging apps (Facebook messenger, Whatsapp, BBM, yahoo messenger, etc)
screen brightness turn up almost all the time
facebook/instagram/twitter/other social apps.
internet browsing
i never use wi-fi, nfc, bt, gps (safety reasons).
And no, i'm not a drug dealer or a pimp.