Jeff Woolsey recently posted an article that is well worth reading, primarily about the VMware VTAX and showing some examples of licensing cost comparisons of common VSphere 5.0 configurations vs. Hyper-V, but also talking about some of the new features of Windows Server “8” Hyper-V, namely Hyper-V Replica.

You'll find the article on the Microsoft Windows Virtualization Team Blog here - http://blogs.technet.com/b/virtualization/archive/2011/08/01/beware-the-vmware-memory-vtax-plus-good-news-for-hyper-v.aspx