When last I installed arch, there was a limit in the kernel that couldn't boot zfs for some reason, but otherwise tried it and liked what I saw. I'm more interested in encryption+boot if possible, but don't know anyone using zfs for anything real yet.
I'd like to replace my md+luks+lvm setup with something that can do all native for raid+encryption+dynamic volumes, just would love to see someone else doing so already.
-mb