I'm surprised how many people say they would choose to kick to open the game. To me it's kinda obvious- take the ball.
You want to score first, and have the other team play from behind. You don't want to have to keep up with the other team if they score first; You want
them to have to keep up with
you. It puts pressure on the opposition, and that should work in your favor more times than not.
The one time I would say it changes is with wind. If you see a big advantage in one side over the other, then by all means defer, and pick sides.