Here's a quote taken directly from the manual:
"insert the power supply from the top, if the power supply has a build-in 120mm fan or larger, we recommend installing the power supply with its fan facing down"
Now I think virtually every power supply that the OCN members would use has at least a 120mm fan but I simply read the design of the case as allowing either orientation. personally I think I might face the fan up to utilise the vent but if it's getting too dusty or you want it to act as another exhaust (since it is ideally placed to do so at the top of the case) then its entirely possible to put the fan facing down - user preference, which is nice to see in a case design.
What's that about the IHS TIM psyclum, is that the theory around the IB heat problems? I had heard it was about the concentration of heat in a smaller area which meant the coolers weren't being effective but it also makes sense that there could be issues with transferring that heat to the larger surface area of the IHS. Can you give a bit more info on it please, very interested to hear about it.