1) Drop from 30% to 5% in some minutes. iOS 10.x fixed this issue.
2) Now with iOS 11 the battery does even last a day and the phone was extremely slow.
Sure i had issues in the past after 2 years with my Nexus 5 and Galaxy Nexus but both were kind of mid range price ~400 Euros.
But with a high end phone that cost 800 Euros I would expect better quality and also better costumer support.
This xmas i just got myself a ~350 Euros Android and i'm much more happy. After 2 years if the phone has battery issues or whatever i will not be so furious has i am now.
I've been recently moving away from Apple mainly due to Quality / Price ratio. I have a 2012 iMac which is basically useless except from Browsing on the Web. Other companies like Google, Amazon etc... ship good quality devices for much cheaper price. So for me i'm not thinking in buying anything else from Apple.