Don't forget to add something on how the failover will actually occur. Does SCR update active directory to 'repoint' the users outlook to the replica when the main server is inactivated or is this left up to the admin?
Seems incredible but mailbox replication and automatic failover to another server was standard in Notes over 15 years ago.
C'mon guys. If I can maintain two copies of outlook open with replicas uploading and downloading changes why can't Exchange do the same but between two servers. Let me connect to either of the servers. If one fails I can use the other. And don't say clustering.
Building resilient exchange is more of a cross your fingers and hope it never goes wrong.