I have been researching this a lot to determine my best path forward. I currently have no spare parts lying around and no current server.
I really like WHS for the features already mentioned as well as the ability to easily combine other purpose server boxes to run on the same environment. I like the JBOD ease of use for expansion as well, very similar to UnRaid in that respect. But as everyone has mentioned, the mirror backup is ludicrous. And the no op system backup seems very shortsighted.
My primary goal is a single box. With this in mind (and the fact i know NO Linux), it makes Unraid a difficult choice. Difficult because it does EVERYTHING right, except the inability to easily do more than just be an array. I have read all the threads out there on VM ware and running these within Unraid or UnRaid inside a VM. On top of all that, i could still have to learn all bout utilizing a VM and the shortcomings with that software.
Right now, i am leaning towred WHS utilizing FlexRaid to parity every disk. This is the closest i can come to a workable solution.
I would LOVE if you UnRaid experts could provide more information and discussion on these.