Every Android phone is an iPhone killer. Android owns ~80% of the market, to iPhone's ~18% [1]. Having many price points turns out to matter a lot; but, I think even people who are not price sensitive often prefer Android (I certainly do). I've loved every Nexus device I've owned...the pure Android experience is hard to beat, IMHO.
1: http://www.macrumors.com/2016/02/18/ios-android-market-share...