It has recently been reported that Lenovo will be switching from their custom UI to stock Android for their smartphones. This gets to the root of the issue of why I prefer iOS over Android: fragmentation. Apple controls the whole experience so you get a synergy between the hardware and software. Save for the Google phones you have a different company making the hardware and software across the Android environment. Apple may have fewer phone options though that control leads to better phone and software integration. If I were to be interested in switching to an Android phone I would focus solely on the stock Android models(which is a reason I believe Lenovo made the switch too).