Two internal SATA drives in my Mac Pro5,1 6-Core system (which I will be selling this week) are suddenly experiencing failures (bad sectors mainly). I've run Apple diagnostic tests and others, no way to repair them. Of course this happened after I installed 10.9 and began a new Time Machine backup. This afternoon I noticed a Seagate drive in a NAS device is also experiencing the same issues. While trying to copy the data to other drives, I'm researching hard drive reviews. I need large volume disks, 2-4TB's. There is so much information online it's more confusing than beneficial. What are your reviews/experiences/recommendations (if any)? I would greatly appreciate any advice. Thanks!