Hmm, that data isn't a very good sample. They purposely buy the cheapest/largest drives(Price/GB). And they had the largest sample of a particular 3TB Seagate drive, which had most of the faliures. Which would likely be the slower 5900 or 6300 rpm drives. They then go on to state the reliability of Seagate drives improved with the 4TB model, very much in line with the other manufacturers. WD drives being more expensive, they didn't have very many, and only in the smaller capacities.
OS drives are typically 7200rpm and single platter if they are kept small. Only two read/write heads and light weight armature for less stress on the motor's bearings. Multi-platter drives add complication and reduce reliability for increased size. Enterprise class drives are priced they way there are for a reason.
Not really sure who I trust to rate these things anymore.
Now were you to overclock the R9-380 a little bit, or pick one that is already a bit faster, I would say it is the better choice. But 2GB or 4GB makes little performance difference at 1920x1080, but if you intend 2560x1440 then I think the R9-380 is also a good idea. It is the performance in specific titles where you start to make a choice between similar levels of GPU. I tend toward Nvidia because a lot of the games I play are Nvidia centric and I do enjoy a good PhysX experience. (Also like to keep the owner's of the 3DFX brand around, I still can't believe they haven't marketed that name yet)
In this case the highly overclocked GTX960 1.28Ghz (vs 1.15Ghz stock) more then makes up the gap to the roughly 10% faster R9-380 at 980Mhz (970Mhz stock), and at 70 less watts. But then you have free-sync g-sync arguments (free-sync being much cheaper). Or the HDMI 2.0 port which may come in handy on the GTX960.