We've been considering building a mailbox cluster running on VMware ESX4.1, Windows 2008R2 for a critical remote site 700 users. Were looking at VMware for many of the obvious virtualization benefits including its small hardware foot print, in a very small MDF. We can assume that ample resources are available for each Exch node since new hardware (very likely oversized, for future use) will be purchased along with SAN Storage. A 10GB link will be used (dedicated fiber) back to main site. What I am interested in knowing is if there are any drawbacks or other considerations to running Exchange over VMware for this project.