David, if you want the older version, you can get a new one for $150.
http://socaltropicalfishoutlet.com/catalog/ecotech-marine-vortech-mp10-p-30.html
If you want a used one, check out Nano-Reef.com. They have been going for $125 shipped on there recently.
I have an MP10ES and don't notice any noise. The tank is pretty quiet since we don't have any fans for the LEDs, and I can only hear the vortech if I put my ear right by it! It's pretty sweet!