I wouldn't buy that one eitherI didn't understand that price difference either.
The Russian scares me a bit (I'm not 100% convinced the cod war is over)
They do come up now and then on ebay in Aus. If I see one I'll let you know.
Have you thought about the new Sigma 50-100 f1.8 ? Shorter range I know, but seems to be one hell of a lens, buy new for Au$1300.