I got my 6 plus for a couple of months now and coming from android there’s a lot to hate and little to like.
First of all as a power user and an app developer iOS is extremely strict, from limiting to coding ONLY on a mac( can’t use Swift on a PC) all the way to app censoring and filtering for a lot of minor details.
Second of all iTunes. I have both Mac and PC and have done my researches and get this, Apple almost intentionally code the iTunes to be a CPU and memory hog ESPECIALLY on a PC. My laptop would literally scream at the top of its lung even on idle and no iPhone plugged in.
The rest are just mostly nitpicking like very hard to even set your own ringtone, limited file transfer capability and so on.