it is not always canon certainly

have the objective now since 1st week'm on my 40d and, as far as I can assess the far, very satisfied with it. It draws really crisp and beautiful images, the wonderful depth of field is very noteworthy and the macro capability is also not bad. And the feel is anyway the Oberhammer, really EX-like. Nothing rattles, the processing can look very sophisticated and the adjustment of the focal ring is pleasant cumbersome, thus not accidental changing the focal length with tilting the camera up or down.
And by now time to provide clarity about: The lens is internally focused! Thus, no turning of the front lens and polarizing filter holder possible. But HSM has only the Nikon version. The AF motor of the Sigma is a little loud, but he usually sits perfectly and is also fast. And in an emergency, after all, can ma fokussiern manually, you should feel the AF sound disturbing. For me it is not a problem, as there is in my opinion worse things on a lens for exposure.
There are so far not much (or nothing at all?) What I could criticize .. therefore from me it (2,8er alone because of the price compared to the Canon) 5 stars.