On my Windows Azure trial account I created a large virtual server with Windows Server 2008R2 64-bit and testet it with CrystalDiskMark 3.0.2.
As showen below, the result was quite amazing.
I was later told that storage for a customer on Windows Azure at the first i placed on SSD-disks. Later on the storage is moved away from SSD-disks and placed on a ordinary magnetic spindel disks according to your required workload.