The 6 has excellent battery life unless you live on your phone. I have a 6+ and run my company out of it and always have over 50% remaining after many phone calls, emails, texts, etc!
The 6 has a pretty good battery life as said. When I had it, I had no problem using it during the day & charge it at night. When I get home i usually had 40 or 30% remaining (Texts via whatsapp, push mail & data use).
It can lasts around 4hrs and a half in non stop use (at least it was like that for me).
With my typical use of email, texting, social media, music, occasional phone calls, maybe some Youtube and Google Maps I can get about 8-10 hours of usage time spread over 1.5 - 2 days of standby.
6-7 of usage over 1 day.... I have all features enabled (no sense in buying a pricey smartphone just to disable every good feature) and I'm using it mostly in a poor signal strength area under LTE coverage.
I've never actually checked the figures as battery life isn't an issue with my iPhone 6. I admit I'm not on the phone all day but it's very rare I ever need to charge it during the day and there's usually plenty of life remaining when I do put it on charge at bedtime.