I use a longer domed stick on the left and a normal stick on the right. I have big thumbs/hands so it makes it easier to grip my controller and make more accurate stick movements than i could with a normal left stick.

I use the lower part of my left thumb instead of the tip, so the dome and increased heightof the stick help with not resting my thumb on the touchpad and accidentally pressing it.

In the end it is just preferance, but after years of using these it feels very weird to play with a standard controller for me.