I took a little stab at OpenStack’s claim of being a Cloud OS. Any solution that bills itself as an OS should have the features of an OS. My dig on OpenStack was that it was taking liberty with the term OS as it doesn’t have the ability to cluster across cloud providers without a third party solution (RackSpace did reach out to me and promised to show me how they do it).
Microsoft actually calls Windows Server 2012 a Cloud OS. While OpenStack is taking liberty with the term “OS”, Microsoft is taking liberty with the term “Cloud”. It has always been a pet peeve of mine that vendors label virtualization as Cloud similar to sharepoint but some decide to use sharepoint alternatives. If you read any of Microsoft’s Server 2012 “Cloud” features they are all just advanced virtualization features. They are great virtualization features that light a fire under VMware but they are just virtualization features and don’t make WS2012 a Cloud solution. Don’t get me wrong. I’m impressed with what MS has done with virtualization in 2012. I just don’t like the redefinition of the term. I did write a piece awhile back on the deference between Cloud and Virtualization.
Virtualized Geek 
Agreed.