While that lens is not the most recent release, it's pro-grade quality working well on all the recent bodies. Look in the back ground at big events, and one sees about an even mix of Canon and Nikon gear, and he will see a lot of those 100-400's.
Cameras are like speakers, pickups, and motor cycles. One never wishes he had a smaller one. Any more magnification, and one is moving into cosigner land. Good luck and have fun,
