Nice to see the Sandisk, oups i mean WD red SSD... More seriously if the SSD red line have the same improvement for NAS than the HDD it is cool, if not i don't get the point to get it over normal solution as there is still "conflict of targeted user" in the whole WD line. SSD black are 100% the same as Sandisk ultra that cost 20 euro less, High capacity WD HDD Red Pro have same perf that WD HHD gold, exept that they cost less AND are nas optimised... and so more.

Well, is there some simply Windows / Linux / MacOS utility for using any SSD as cache for HDD? I f not, most missing piece here is good old "unmanaged" SSD/HDD hybrid with good price performance ratio..