Got some infos from an friend, using the old and the new AF-S VR 80-400mm 4.5-5.6G ED lens:
He got it some days ago and was on a trip in the south of Italy.
He told me that the new lens has an much faster AF than the predecessor model. But the AF was even not accurate every time. In his opinion Nikon pushed the AF-S VR 80-400mm 4.5-5.6G ED up in image quality and made it faster. But he doubts that he did right by buing this lens, spending 2,5 times more than his old lens costs today. Excellent rumors and advertisements are sometimes not true, as we all know.
Maybe Canon improves the lens too, but will it be 2500-3000€ worth - in comparison to the old 100-400? Let us see.