Does anyone have any experience with the WD 4TB Studio USB 3 (bit.ly/dOtPpS) for about $250, the 4TB G-Drive USB 3 (http://bit.ly/27ZydU) for about $350, and/or the WD 6TB Duo Thunderbolt (http://bit.ly/z2UA9b) for about $525+? I'm looking for a external for my 2012 iMac allocated to iTunes media, Aperture libraries, and digital video footage. I'm a hobbyist (i.e., not a professional), so the absolute "best" performance isn't critical, though reliability is. I back up data from 3 laptops and some data from the iMac via Time Machine to a networked Time Capsule, and the rest of the iMac data via Firewire 800 to a (slow) Drobo. Any alternate suggestions would be appreciated also. Thanks.