@gunt76: Obviously, the specs of the Duo are better than those of its predecessors. But even the Duo is an inferior product compared to any Synology Disk Station: support is still lacking, there are still reports of overheating, modding has still to be done via the insecure and obsolete optware. Synology DS comes with a very advanced OS, which offers you one click packages both from Synology and the community. With Synology SSH is also one mouse click away, but you generally don't need it.
If you're happy with your WD MBDL, good for you. But once you've experienced the quality of Synology products, you'll never want to go back to a WD NAS.
Anyway, I'm not advertizing, I just want to give some advice based on my own experience and what I've read from other users so far. I'm sure one can have fun with a My Book, but don't put your life on it, to paraphrase WD's advertisements. I did and lost my data when my disk died from overheating.