I've just built a Synology NAS for myself using a couple 8Tb Red - happy as a clam! I have 2 extra bays free in the NAS, and Synology allows transparent migration from a RAID-1 array to a RAID-5 one, so I can drop 16 Tb of extra storage tomorrow and get them as pure storage with better performance. Happy!
ANDYWIRYAPEACEFUL, the 7200 rpm will probably be a minus for the Reds. These are the only series that give you HDD with a significantly lower power consumption - just check the specs and check the NAS disks from Seagate for instance or any other model you choose. Yes the specs are mostly correct, I have 6 DIY boxes that one can call NAS or NAS-like (in some cases ) and both the power consumption and temperatures are notably lower than boxes filled with other disks. The performance is good, especially for storage and not great, but acceptable for application usage as the review said - it applies to the old models even more. The balance of the features is Ok in my opinion and speeding the platters up will only give you something like a not so good equivalent to the new Gold series. The Golds are very quiet, but their temperatures are not as low as with the Reds, they are also faster and much better in random access scenarios - much better than what you would expect from just speeding up the rotation. So, every scenario has its specific demands and after using these for a few years I find them quite well designed for the most NAS usage scenarios. as for the bad sectors KELLYSI mentioned - I had some problems too, but in each case (thankfully) everything was corrected after full format (takes a lot of time with these capacities) - from 10+ Reds this happened to only one and it was from the first 3TB models (6TB were not available yet).
Would love to have seen HGST He12 or He10 included.
They sell for less here, and is remarkable quiet (about same, or lower, as my current WD green 5400rpm, that they replaced, vs the 7200rpm).
They use quite low power as well.
And yes, i would else agree with 5400rpm is better for consumers for archive usage.