One thing that does suck about these rigs is that they do not run very stable when fully populated (ie all 16 cards installed).
This is very dependent upon power supplies. You need a beefy PSU with stable 12V rails in order to keep the amperage even to all 16 cards.
Hmm, do you have any recommendations. Believe it or not I'm running one full rig with a seasonic 550 watt 80 plus gold psu but I'm thinking of buying something more beefy. I have in mind the AX860 series.