Long time ago I use to play Games with arrow Keys cause thts the controls for Kinda old games n wen i was still young but now games like CoD, Medal of honour, its best 2 play with WASD n + I'm right handed.
For instance, when I'm using a mouse for absolutely ANYTHING, I prefer WASD so I don't have to put my hand on my right leg (I normally type with the keyboard in my lap). I prefer the arrow keys if it's solely keyboard control.
they both work good for me, like onslaught, using wasd is easier because you have to use the mouse, but in exit path you only use the arrows and the spacebar, but i think im kinda ambidextrous like that.
I use the arrow keys, but in an odd way if I'm also using the mouse.
I have my thumb on the left arrow, my index finger alternating between the down arrow and the right arrow, (or index on down and middle on right) and my ring finger on the up arrow.
It's really odd as I've figured out, but it works quite well for arrow movement mouse click shooters. :P
i use arrow keys when using mouse because my left hand is on arrow keys and it comforable when ring and pointer control side keys and middle finger controls up and down and if space bar is required i use wasd and thumb hits space