Project blackbox is a cool idea from Sun; it's a very easy way to get a whole bunch of computing power at your fingertips in a really short period of time. The whole concept of fitting everything into a standard cargo container is ingenious. That way you can leverage the existing shipping and transportation infrastructure to move a blackbox around for you. No special trucks needed, neither are there a ton of boxes to be delivered, unpacked, wired up, tested etc. All you need on the ground is water, power and a fast network connection. Very cool.
Project Orangebox on the other hand, while being very simple has the problem of seasonality and spoilage. Limited time usage, especially if you're overclocking. But it's easier on the environment, so in the end, it's a wash.
Thanks to Tim for the links.