Can't speak for v7 and Exchange 2013, but I can relay some of our experiences with 6.x and Exchange 2010. Apologies. if I teaching my granny to suck eggs here.
With regard to storage presentation; if you want to use snapmanager for Exchange you'll need to use Snapdrive. The choice is then to how to connect from the VM to the storage, the simplest way is running the MS ISCSI software initiator within the VM but this does have a performance hit, as with any other server application it's going to be dependent on what splice of the CPU it can get. If you present the storage to VMWare via ISCSI instead the connection is running at hypervisor level, much like it would with a fibre channel connection, this configuration works and is supported with the snap products.