I don't have customer experience, but I was part of the development team that implemented Exchange protection in VMware backups. I've been supporting Exchange in the CFT team since I left development. Here are some points to consider:
MS-Windows policies exclude Exchange data files in order to avoid redundancy with your Exchange policy backups. The exclusion is not configurable. VMware policy backups do not exclude Exchange data files. A combination of VMware and Exchange policies would backup up the Exchange data twice.
A VMware policy that protects Exchange, SharePoint, or SQL Server creates an extra job called Application State Capture (ASC) that runs before the VMware snapshot. The Exchange ASC job takes a temporary snapshot from which it catalogs the databases and their mailboxes. The data is backed up in the VMware snapshot and backup. The ASC job does not truncate Exchange logs; the VMware snapshot job does that.
A VMware backup catalogs only the Exchange databases that are active on the VM. In that way, you can back up all your VMs and only truncate the logs once for each database. Then all the logs needed for restore are contained in the backups of one VM.
The NetBackup client installation includes a Veritas snapshot provider. (This has been known in the past as the Backup Exec provider and the Symantec provider.) This is necessary in order to a) take an application-consistent snapshot, b) get a snapshot of the VM that the Exchange VSS Writer recognizes as a full backup snapshot in order to truncate logs, and c) identify to Exchange which databases are backed up so that only logs for those databases are truncated.
In an Exchange policy backup with GRT enabled, there are two opportunities to get a list of mailboxes to catalog in the backup - discovery before the backup, or failing that, enumeration during snapshot processing. In a VMware policy backup, the mailboxes must be discovered before the backup, because the ASC job does not take the time that would be needed to enumerate them during snapshot processing.