Nice test-run Eric! I've seen you took a lot of shots at focal lengths above 200mm but in most cases you also could have stepped a little closer to the action. Now what is it that sold you on this lens: The reach, the IS, the IQ?
The reach mainly, the IS is like icing on the cake - if money was no option, I'd probably rather get the high end, 70-200mm f/2.8L IS USM lens. That F2.8 would be nicer as he gets into faster sports and future, nighttime games.
As for stepping closer, actually, that wasn't an option as my wife (the photographer for the TBall game) had to stay behind the chain-link backstop fence.
I think I'm very spoiled for my camcorder lens, a GL-1
(I've read that it has the equivalent of something like 50 - 800mm)