Whatever you do, I'd advise against buying all your disks from one source. If there is a bad batch, you could be be buying a whole set of bad disks. You can see this in product reviews on some competitor websites, five star reviews, then a wave of one star complaints when the bad batch hits and then back to five star reviews wondering what all the one star reviews were about.
I'd buy identical drives but from different sources, so for example I bought one of my 1TB drives from OcUK and one from a competitor.