I've been running a 6tb RAID 5 set with WD green, they have never given any problems (RR2314).
I choose the green disks because their inherent design puts less stress on the internals, they are about conserving power and generating less heat, they are whisper quite as well.
Less power drawn for each disk means my IcyDock external enclosure fan runs quite. Also less power drawn means the IcyDock power supply is not working hard all the time. I do have an exact spare IcyDock enclosure just incase.
Which means better MTFB to me!
They are slower as individual disks, but I get decent performance in RAID 5 of around 160mbps, which is good enough for HD video streaming.
BTW: My RAID is on 24/7, it never gets switched off.