King of the hill for 4"7 still sony Z3c . Whopping 101hours ER on gsmarena. Strange the endurance rating for 6+ like not really good.

Safari definitely refresh if open too many , i assume over 8 is too many. Other browsers tend to refresh too but crash is more often observed. Yes its a very annoying problem to me and Android not having this refresh problem. So if you ask me RAM does make a difference here.

Maybe i will skip the iphone and get ipad instead to replace my retina mini if that is true.
Got one question here , photo synced to iphone able to delete it by phone itself or i need to remove it via itunes ?

Does the iphone still have the restriction of 10 mins background download limit before the system kill off the data?

i am not 6+ owner but coming soon , size should not be a problem to you if you are using note series.
As the past experience the annoying problem for me would be

1. Unable to manage photo and video nicely and neatly on iOS , can only delete photo from camera roll , others need to remove via itunes sync.
2. App are not able to access system level so makes sharing photo via gallery directly to whatsapp line wechat etc a bit hassle.
3. Background download limit 10 minutes , the screen need to be awake and on the app to continue the download.
4. No torrent
and a few more now cannot remember lol

What makes me back to iOS is the 6+ screen size , battery life and the experience , experience in term of using the apps in iOS is truly awesome. Like reading the flipboard , facebook , wechat etc. Also invested alot in iOS app LOL