Hi, I'm putting together a storage solution to go with my Mac and I'm struggling to figure out which way to go. I'm primarily going to be using it for Time Machine backups and storing iTunes media on it to be streamed to the apple tv. My two choices are: A WD 8TB MyBook Duo (http://www.amazon.co.uk/8TB-Book-Du...5?s=computers&ie=UTF8&qid=1442861824&sr=1-125) A Drobo DDR3A21 (http://www.amazon.co.uk/Drobo-DDR3A...&ie=UTF8&qid=1442862049&sr=1-1&keywords=drobo) with a few WD Red drives in it. My question is how much benefit I really get for the considerable extra expense of the Drobo? The Drobo on its own is nearly as much as the WD MyBook and that's before I add drives. What do you think?