MY BIGGEST REASON:
Controller preference. I am 6'5 and fairly big. can you palm a basketball? well that is nothing for me. 10 minutes with a ps3 controller and my hands are cramped up. It hardly makes it a choice. I even tried ps3 controllers designed to feel like 360 controllers but they all felt too damn cheap.
http://imageshack.com/a/img801/6426/f7pc.gif
^Yes that's me ripping it up in the GIF. :)