That is rather inexpensive for the PCI-e. Not sure how many people run them in an array. The problem with PCI-e is your can't run the hard drive in bays for hot swapping.
I don't know if it will be any faster in each VM, it just keeps it cleaner. Besides moving the VMs, it is nice to be able to make a snapshot of AC in a separate VM so you can go back if you need to without causing another app to go back as well.
It may be like your SBS, etc., but Small Business Server, by definition, came with certain server products like Exchange and SharePoint and was designed to set up everything with wizards.
