I would never own an iPhone, I just can't get along with the limitations (no replaceable battery) and the funky text editor, its just cumbersome compared to my Android (currently using LG-G5). However I will only use an iPad to fly my Phantoms, because they work the best IMO.
A year ago I tried 3 different android tablets because that's my preferred OS, even the most expensive high res Samsung. Two weeks of work, buying and returning. I couldn't get them to work right, too much lag, even with all the tricks, deletions and special settings that were advised in this forum. No joy.
So I tried my wife's iPad, it worked perfect, minimal lag, decent brightness, good response. That was 14 months ago. Maybe things have improved on Android devices, but I like the iPad for flying. However I rarely use the iPad for anything else, because of the stupid IOS text editor.