iOS only! I think it's really easy to use and I like their design! However I do not doubt that Android is quite good but iOS will always be better. 
Nice of you to acknowledge some value for Android.
Never say never and always seems to me an even stronger word than never. The figures show some tendencies - for example Apple Cedes Market Share in Smartphone Operating System Market.
In the end (at least for me) is important to have multiple choices even if some of those choices mean that we do not have much customization freedom. Some need to keep it simple...