I'm using Multistore, with iSCSI/NFS and CIFS/NFS vfilers.
I use iscsi/nfs vfilers for my virtual infrastructure (VMware), and the CIFS/NFS for user homes.
The "homes" vfiler is connected to an AD domain and is working fine.
I also tried data migration, and it does work as announced. I can move vfilers from between storage heads without any disruption to the traffic.
Also, most NetApp software was updated to support vfiler, so that's no longer an issue.
The main quirk is that filerview and system manager does not work with vfilers. On a Multistore filer you are only able to use filerview or system manager on the vfiler0 (physical filer). So be sure to be familiar with the CLI.