@Mark Hodges:
I think you're overestimating the downtime associated with VMHA in most environments. VMHA requires shared storage. Every major shared storage platform I can think of offers snapshot functionality with very quick restore, and most of them offer VMWare and Exchange integration.
If you lose either the database or the OS, you can be up and running in far less than an hour using snapshot, clone, or CDP functionality. To be sure, recovery from corruption is not automatic, but it's definitely not a 2 day operation. In many cases, customers feel the possibility of a little extra downtime is better than having to procure, provision, maintain, and monitor 2-3 copies of the database and the requisite 2-3 servers.