these are my first matches on a 400 and what a difference it makes. I have shot the last couple of MLS seasons on a 300mm which is a fantastic length, but the 400 puts you in the game for so much more of the field. I'm glued to the eyepiece way more than I was on the 300. Shots inside the box are much more difficult to get in a hurry as there isn't as much room above and below the player, so a 70-200 on a 2nd body is ideal.
I understand this quite nicely, and i do have a 2nd body and 70-200 sitting next to me, but i can't imagine to use 400 instead of 300, what the joy in that is really what keeping me itching about it.