And for two HC2, we are close to the price of the Helios4 solution with PSU included :
What do you think about the Helios4 ?
But 2 HC2 costs a bit less than a 2 bay Synology or QNAP NAS.
The Helios4 looks nice. But I don't have any personal experience from it. Also it doesn't seem to be available for purchase at the moment? And I really don't like the fans.
With two (or more) HC2 I get hardware redundancy if one unit fail and also a distributed load. More memory and computing power. But I need more network ports and cables.
I won't switch from HC2 to Helios. But it might perhaps be a better alternative as a first NAS if you really need 4 x 8-12 TB disks.
I suspect many buy Helios4 and put in 4 x 4-6TB HDDs in RAID 10 or RAID 5/6. Or even without RAID. That I think would be silly. Two HC2 with 8-12TB HDDs would beat that.
But Helios4 with 4 x 8-12TB HDDs without RAID would be more cost effective storage than 4 HC2 with the same HDDs.