The major selling point of Microsoft Azure for me is that RDMA over Infiniband is supported on select machine types. This type of networking technology is necessarily for important classes of applications (HPC) as well as for new types of infrastructure (e.g. memory clouds). Yet, so far RDMA networking in Azure is only available on their Windows VMs. I've seen mention that Linux support is in the works, but the last time I checked a couple months ago it was still not supported.