Still yet to do it but from what i've seen and heard it's a great improvement that's for sure especially with the possible story to continue on with later.
Haven't done new RFC but have done Scholo/SM. The gear is nice for leveling characters and the re-designs are fantastic. Loving the new high-res texture work.
There's also a few items (mostly helms) that only share models with MoP gear, so if you're looking for some fresh transmogs these are the places to go.