GoinAllTheWay,
If I didn't want a few features of the nas, I'd just buy two 8tb externals if I were you.
They're under $250 each and you can have one be the backup. Going the TS 451+ route will cost double or more with the drives, and Raid 5 means you'll lose a bunch of storage to redundancy.
In fact were that option available when I got the 451, I might have gone that route instead myself. The technology changes so quickly, and you could even use a computer laying around networked to host those drives, and install software to make it behave very much like a NAS. Downside is it will suck power and you'll need at least one dedicated desktop on all the time.
And, I remember so much frustration with WHS, I was on the main forums at the time reading hundreds of posts looking for solutions, and it seemed Microsoft was just abandoning it, there was no light at the end of the tunnel. That may have changed by now, I don't know, more importantly, I no longer care
Edit: and yeah, Synology gets great reviews, compare that to the Qnap before you buy, I don't know much about it.