There is a great post on the VMware blogs that talks about how ESXi is not only easier to install but is quicker to install then Hyper-v from Microsoft. One of the more interesting stats that they have is that hyper-v takes seven reboots compared to one reboot of ESXi. It will be interesting to see the improvements that Microsoft will make in the coming months to their product. One thing for certain is that VMware still has a dominant lead over Microsoft in visualization technology.
VMware blog post
Install video of ESXi vs. Hyper-V