IBM Verse looks pretty well and every customer with a Domino server can use it.
It's quite common to run the mail service on a cluster. But if you following the IBM Verse On-Premises 1.0.3 Administrator Documentation, (Installing and configuring)
you will struggle at the point, where the cluster is important. – at the CREDSTORE!
IBM Notes will become an additional column "Sender" in the email view Inbox. Adding up to the senders' name "Who" this column will show the email address of the sender.
Furthermore on the "email details" will be automatically shown in the mails' preview and open emails per default.