My 2 cents:
There are what I consider uncommon instances where true HA is a requirement -- particularly from a 'protection of guest memory space' perspective.
To get specific SAP has an Enqueue Replication Service (ERS) responsible for maintaining remote database state (simplified explanation) in RAM that absolutely must be deployed in a manner that guarantees that the OS's involved in delivering this are not powered off (thereby losing memory state).
VMware HA can not meet this requirement.
MSCS on VI3.5 can and it is
fully supported in a multi-host configuration as long as the Cluster does not exceed 2-nodes.
So...this is not a high value cost savings opportunity but since HA/DRS are not required you can reduce some of your licensing cost and still end up deploying less Physical Hardware -- i.e. we can deliver this capability in a data center leveraging 2 VI-3 Physical Hosts (hosting two 2-node clusters) vs. funding 4 separate physical Servers.
Yes - we have to make sure the OS partition resides on a local (to each physical host) VMFS partition and that we leverage RDM's for Shared Disk (Quorom and App) but in my mind it is not as complicated as some folks make it out to be.
just kidding (so to speak ...) 