I am a bit confused about one of the benefits of managed disks that is often cited - reliability. That is, azure automatically stores the disks for VM on separate stamps, so they both don't go down at the same time. But don't they keep locally redundant copies of disks (even unmanaged disks) anyways? Then why would someone creating managed disks (is it mainly for other benefits of manageability, and snapshots)
One of the other key differences for me is the ability to use resource tags, resource locks and role based access control at a disk level. Unmanaged disks only support this at the storage account level, which would apply to all disks in that storage account.
For more information on the differences, check out: