I have never put much thought into that, I mean the 360 gamepad sticks are far superior to the DS3 sticks that is no brainer

This is exactly right.

If you have different thumb lengths, you should use asymmetrical.

If you're a normal human being, your thumbs are the same length, so they should always prefer symmetrical. People suggesting otherwise are just being fans. If you argue the thumbs naturally go to the top, you can't argue that they should be offset, you can only argue the sticks should be above the other buttons - BOTH sticks, not one.

This is hillarious. How do you hold your controller? I hold it like a normal person, left thumb on the stick, right thumb on the buttons. Guess what? Those are on the same position.

Just test it with your right thumb: Imagine you're using a symmetrical gamepad where both thumbsticks are placed on the height of the left stick of the 360-pad. That may be the most comfortable design, BUT... try to press the square/X button to reload in whatever game and (as quickly as possible) return to the right stick.

Now imagine doing the same procedure on a 360-pad: This way you are slightly faster. The left stick's position is the most comfortable, and because the D-pad is not used as often as the stick almost efficiently perfect. The right stick's position is not the most comfortable but gives the upper hand in reaction; switching between the right stick and buttons happens considerably more often so it is efficiently perfect.

Short: The asymmetrical thumbsticks the 360-pad has to offer are the best balance between a comfortable and efficient design -> the most ergonomic design.

I hold both sticks, you must only play games that have fixed cameras...

I agree that for games that demand heavy manual camera control symmetrical sticks may be more comfortable. Third person and first person shooters for example. For every other game, asymmetrical sticks is the way to go. This includes: sports games, racing games, RPGs, action games, fighting games, platformers, etc...

So we've come to agree that fixed cam = asymmetrical. free cam = symmetrical. I'm good with that.

WiiU pro controller still works out better for when you use the D-PAD +buttons or the Stick + buttons.

I admit I seldomly play shooters on my 360. But fixed camera / free camera may indeed very well be the underlying determining factor for controller preference!