Curious if anyone has had the opportunity to try both or if anyone has either currently and their recommendation. Looking to add secondary storage for an all SSD Mac mini setup. Its going to hold iphoto, aperture, itunes libraries, final cut pro x and logic express files and most of my data. While the mini will house the OS and applications. I was thinking of getting the smallest/cheapest of the two and upgrading the drives later to having atleast 3TB of usable space, so really the current config of one is not important. I hear the MyBook Thunderbolt Duo is user serviceable and seems you can add whatever matching drives you want in there. If I go that route i'd most likely add 2x3TB Western Digital Black drives for faster performance. TO ME atleast it seems the western digital is the best choice for price/options, I'm familiar with WD's RMA process (not necessarily a bad thing), not sure about Promise's have heard mixed reviews on that. Ultimately something clean and efficient that I can utilize and upgrade along the way would be the most ideal. any thoughts? experiences? Thanks!