I shearched long for a good zoom in the range of 70-300.
Finally after using 70-200 I got to Sigma EX 100-300 F4 DX HSM. Fortunately I got the new version due to some delay in decision making.
I am just amazed by the sharpness, even do F4 looks firstly somewhat slow, I found it very easy, as the focus works superfast.
Pictures are well balanced in color, aberration is nearly non existent. The triphood ring I found also good and easy to use.
Would just reccomend it, but as others said, it's a huge lens. But worth every penny.