Arregui - put him in post 2 and he has a disadvantage in that if the other player serves deep Arregui will likely not get the ball over the server's head on the return. He does do a good job of keeping it close to the side wall though.
Now put Arregui in post 1 and if he serves deep then either the opponent will also not be able to pass him OR they will throw a big left side that will go over Arregui's head but come out for an easy rebote where he is deadly.
Post 1 vs Post 2 is a big difference in my opinion for Arregui.
