I can personally recomend the 'Meza 11 NEO'
It's very clear is very good for the price, supprisingly its quite fair in all frequencys.
(Source: Audiophile)
I have stuck with iOS 10 for a while, If you were wondering it was due to software I require...
I have seperate devices on iOS 11 and I haven't seen a diffrence.
I am having the problem with battery life too, I have had it since last November but over the last two (or so) months it has been draining so much quicker...