traditional RDMs versus NPIV RDMs

Hi folks -- I am trying to test out NPIV storage for guests versus RDMs in physical mode -- please correct my understanding and also please kindly add any additional advanatages as you see fit

1. with NPIV - there is additional security for the LUNs   - as the VM that is supposed to see the LUN --  is going to  have access to it

2.all mmultipathing is still done at host level

3.we cannot get over the 256 luns per host limit still --

4.we can easily migrate a VM from cluster to the other without having to do rezoning/reprovisioning

thanks in advance,