Hi Eric. I tested Variphy several years ago and they have a good product. I did see Akkadian labs at Cisco Live back in June and their products look really good. I also had a session on Prime Collaboration Provision using the new 12.x version and it looked just as impressive although not as appealing to the eye as the other two vendors. Plus PCP/A also gives you the ability to monitor your SIP trunks and G/Ws.
I know that you can install the base version of PCP at no cost. But you have to pay for the advanced version of Assurance to get long term data logging.
HTH, Chris