Vmware : What level of consistency do I get?

That depends on what version of vSphere you are running and what Guest OS you have.

* Special requirements for application consistency on Windows 2008/R2, see below.

• Dynamic Disks are not supported
• SCSI disks only
• disk.EnableUUID attribute must be enabled.
• Enabled default on VMs created on vSphere 4.1
• VMs created on prior vSphere 4.1, following procedure must be followed:
• Power off your Windows 2008 VM
• Edit Settings - Options - General - Configurations Parameters - Add Row - Name=disk.EnableUUID Value=true

To make sure all your VMs have Legato Sync Driver Disabled, VSS Enabled and disk.EnableUUID configured correctly will take a serious amount of time if you have to connect to each VM manually and verify everything.