I hadn't seen too much talk about it, but since I was redoing my NAS I figured it would be a good time to try using btrfs as the filesystem for storage instead of mdadm/ext4.
Instead of using the (very nice!) WebUI setup a RAID, used the CLI to run something to the effect of:
Then I was able to see the newly created FS in the WebUI and it's been gravy since. It uses it just like I would expect a normal storage location to be used.
Plus, now I get all the benefits of having a filesystem that does file level check sums and protects against bitrot or bit flips.