All gamepads that have it having a BAXY control scheme. That's B right, A down, X left, Y up for the buttons on the right side of the gamepad. I can't tell you how many times I have pressed the wrong buttons when playing certain games all because the 3rd party switch controller I have uses ABYX or because I don't remember where the symbols are on a PlayStation controller. Dreamcast and original Xbox had their shit together with how they used BAXY for their controllers and to this day I may shit on Microsoft, but not on the BAXY control scheme on their gamepads.
Purely preference. That, and I've spent about a million times more time on an xbox360 than just about any other console in existence, so it's what I personally consider the best way. If you or someone you know uses any other way, that's your deal, but I just can't retrain myself to like any other format.