Just mentioning, those struggling with Citrix XenServer, don't waste your time. I've tried every trick in the book for about 4 months, still pfSense would perform bad compared to other solutions.
My suggestion is, like MasterX-BKC, go for VMWare for virtualized instances of pfSense. The downside is that VMWare doesn't support migrations and backup solutions out of the box in the free version. Multiple 3rd party plugin backup alternatives are available for a lot less cost than buying a VMWare license.