Is it safe to run pfSense in a VM?

I have a computer with an i3-processor and 4GB ram, that has been a dedicated pfSense router for the past year.

This is of course a little overkill, so i have tested OpenVZ on another computer and love it. Now i wonder if it would be safe to put pfSense on a VM, and how i should set it up to secure it.

My computer has only one networ-port, and no room for expansion, so i have set it up with different vlans.

Any input is greatly appreciated (and if this is the wrong sub, please redirect me)!