I am in the process of planning to upgrade my domain controllers. I am currently running Server 2003. I have a couple of questions as I am podering a few different configurations. Are there any known issues with making you domain controllers virtual vs physical? I am running ESXi 5.1 with 3 hosts in an HA configuration. Also, what are the pros/cons of upgrading all the way to Server 2012 versus Server 2008 R2?