Every implementation needs a differentiating factor. AWS is its flexibility and ridiculous amount of built-in functionality - message queues, databases, DNS, storage, map reduce, etc. Azure moving from one-click deploy to the cloud to one-click deploy to your own cloud is amazing. It's the primary appeal of OpenStack for me.

The real question will be what will this take? If I have to put Windows Server 20xx on my hardware to run the fabric, I'm out.