I use pfSense as a vitual machine to firewall/NAT off my vitual environment. It works great. I am running it on KVM/QEMU and handing off the PCI device to the pfSense VM. Great for managing my environment through VPN.

I've also used this in a retail chain in DC/MD/VA. Each location used pfSense for site-site VPN (OpenVPN). We also used the asterisk package to handle VoIP.

Overall, pfSense is a robust UTM.