Jeff posted part 2 of ‘Hypervisor Footprint' debate, this time, compares the full Windows Server 2008 Hyper-V, with the full VMware ESX 3.5. “Now consider the fact that there were two significant quality and reliability issues with two major updates in a row (ESX/ESXi Update 2 & Update 3). While the initial Windows Server 2008 Hyper-V release didn’t provide Live Migration (Windows Server 2008 Hyper-V R1 had Quick Migration and Windows Server 2008 Hyper-V R2 includes Live Migration for free), it didn’t include two days of potential downtime and virtual machines unexpectedly rebooting either. For those that track availability in terms of nines (five nines is 5.26 minutes of downtime a year) VMware ESX 3.5 Update 2 dropped customers to “two nines” of availability.
Using VMware’s own metrics, Windows Server 2008 Hyper-V is clearly the winner over ESX 3.5 and by a pretty wide margin.”
Full Article: Virtualization blog