Just a heads-up: There is a CPU usage issue with version 2.x of pfsense running on ESXi. I've spent the better part of the last few days looking for a fix, but without any luck yet.
There are MANY others with the same issue. Basically, pfSense shows very low CPU usage (0-4%) during downloads at 30-40 mbps, but vSphere reports the VM as using upwards of 2000 MHz. Idle is around 500 MHz, streaming tv at a constant 10 mbps bumps this up to around 1000 MHz.
This issue does not appear to affect pfSense 1.x. It does not appear to be related to the vHardware version, pNIC vs. vNIC, vSwitches, cpu architecture, VM tools or ESXi version.
Worst part is, the pfSense developers seems to not care. I haven't checked if the issue also exists on Hyper-V.