Gartner published a new Magic Quadrant in October 2012. For the first time Service Providers delivering Infrastructure as a Service are reviewed.
Amazon Web Services is a clear leader according Gartner.
Gartner reveals in the report the virtualization platform being used by the providers. 9 out of 15 providers listed in the quadrant are using VMware vSphere for server virtualization. 4 are using the open source Xen. 1 is using KVM and 1 is using Citrix XenServer.
Amazon is one of the four providers using Xen.
Some big names are not listed in the quadrant as they did not have public cloud IaaS offerings in general availability by June 2012. For example not included for this reason are Microsoft (which introduced a persistent VM capability into Windows Azure, thereby giving it full IaaS functionality along with PaaS), Google (which introduced Google Compute Engine, an IaaS offering) and HP (which introduced HP Cloud Compute).
Gartner Magic Quandrant for cloud Infrastructure as a Service
A copy of the Gartner report can be requested for free at Savvis or Virtustream.