trying to use RCU 2.1 and had some problems. Read the release notes and found out that QTREEs and vfilers are not supported.
I hope in the next version these are fixed/addressed. QTREE's I can get over, its not that big of a deal really, but vfiler's is really important. We use the vfiler -dr option to snapmirror NFS vmware datastores and therefore can't use the RCU. Using vfilers with the -dr option makes it easy to fail over to another site and is critical to our disaster recovery plan. Also, I think this fits into your future data motion plans.