Only to answer to your question.
I would be interested in the reason, why you have chosen iscsi instead
of nfs. Just because of the license costs?
The cost of license could be a reason, over all if you consider the tiering appliend on 3000 or 6000 family but the real reason is that we've a loto f environment where db with great I/O demand (Exchange with hundreds of mailboxes, Oracle, SQL with dozens of GB of db and so on...) installed on iSCSI SAN using only software initiator (such as the Microsoft) and with great user perception and benchmarked performance.
We also are aware that NFS on NetApp filer is really fast (think to Oracle, also RAC, on NFS!) but up to know we've used for VMware only in limited and little farm of ESX servers. The biggest problem on iSCSI (or F/C) is the oversizing (double) you've to let on volume for snapshot of VMFS stores, the restore that from a snapped LUN is not so easy (I spoke of Vizioncore or Tomato to add value to VM backup, but is another cost) and so on.
Anyway, for any 'transport' you choose to use you can be sure that on NetApp appliances VMware will perform always better than other storage.
PS) just as sample we've setup a VMware cluster on a filer without F/C switches, using a direct attach and letting igroup and lun masking act as switch :-)...this you can have with FAS only!