Yes I've been quiet of late, but for a very good reason... which I'll divulge maybe on the weekend ;-)
But todays news (Alessandro - you are a machine aren't you? When do you sleep!) was just too big to let go by - ESXi is finally free. Well... finally officially free - technically it's been free for ages, all you had to was download a patch for it, as ESXi patches are essentially entire new images (although of course it would've run in eval mode for 60 days... by which time another patch would have come out ;-)
This is a great way for VMware to hit back after the raft of troubles lately. All the arguments from Microsoft, Xen, etc have always been about price, and they no longer have a leg to stand on.
This actually makes Hyper-V more expensive than ESXi, as you still have to pay for the Windows OS in the parent partition. And pay for no less than Enterprise Edition if you want to cluster Hyper-V. Lets not forget the storage add-ons if you want a clustered file system.
This puts the ball squarely back in the competition's court, and might as well be the final nail in the coffin for Citrix XenServer as it is now the only major commercial hypervisor on the market you have to pay for.