Duncan,
May I dissagree with you there? (Purely for exchanging thoughts and learning about this)
I 9/10 times advise the direct use of iscsi to the VM. Reason for this being the not so great MPIO implementation for iSCSI in vSphere / VI-3. I'm not saying it's bad, but if we look at vendor specific MPIO drivers for the VM, they often perform a lot better then a RDM lun.
My latest experience being the Least Queue Depth MPIO that EqualLogic does.
Jelle
@jkalf