To be fair, usage is subjective depending on a variety of factors imo, what other people report is entirely not exactly what you will do in most days, because each person has their own individual way of utilizing their iPhones daily. Some factors include:
1) Signal strength?
2) Wifi all day or 4G all day or a mixture of both.
3) Do you play intensive games
4) Screen brightness level?
5) and many more...
For me I play game quite a bit (Rival Kingdoms and Vain Glory) as two prime examples, quite heavy graphics with the latter being very intensive yet surprisingly my phone never or heats up very little to none... which is impressive in contrast to previous android samsungs i used...
Today I got about 7.5 hours usage time [i have about 3-4 hour screen time on or so if that helps because usage time does not mean screen on time only, it includes background and foreground processes] and 12 hour standby on my 6s+ running samsung chip.
Most of the time I'm on 4G most of the day with a few check ins to wifi, Screen brightness adjusts because I dont use auto brightness, but mostly hangs around the 50% mark.
But given today was my day off I was playing and engaging my phone a lot more than usual on the go around city, therefore I wouldn't expect the usage time to be "HIGH" because i'm constantly engaging the phone a lot most of the day and on screen is a major battery drainer [due to those pixels]
If was in University studying, I could get a higher usage time and standby time with a better % because i dont use the phone often even though i leave wifi on...
So yea, it is hard to ask people how their battery life is like. you have to test it yourself, record what you do, eg 2 hours facebook 1 hour gaming 15min reading emails etc...
then gauge that accordingly... as an example
For me i game a lot so i dont know if that apply to a lot of other 6s/6s+ users. surely if they were not like me they'll get like 10 hours usage no problem
hope this sorta helps, like i said you must test it yourself how u will use that phone on a daily basis... we can't do that for you.