So, just as a quick follow up to my question of adding a 600 or upgrading my 400: https://photography-on-the.net …/showthread.php?t=1389136
This past weekend I upgraded my 400mm 2.8 IS to the Mk II. As well I bought a Benro carbon fibre monopod to replace my trusty Manfrotto 681B.
The combo of the Mk I 400 and 681B tipped the scales at exactly 18 lbs. The new 400 with the Benro pod weighs in at exactly 14 lbs.
So, the cost for me to upgrade after selling my Mk I came to right about $1400 per pound. Yikes!
But I gotta say, the difference when you are running up and down the sidelines at a football game is remarkable. I even noticed the difference the first time I loaded my Think Tank Airport Intl. with my gear for the game and lifted it into the trunk.
All in all, a worthwhile upgrade for me. I am a happy camper. 
