An honest approach had already been discussed, so no need to comment on that.
I have the newer 2.8 version. I love using it for sports. I shoot wide open to get the fastest action shot possible. Plus, I get a little more subject isolation than I would at F4.
Yes, the lens is somewhat heavy, but the IQ is superb. When using the lens handheld, I mount it to my Black Rapid to take the weight off of the hands and arms in between shots which helps a lot. If the 2.8 version is manageable for you (size and weight) I also agree it would be worth trying.