Options for zfs inside a VM backed by zfs on the host

[Vick Khera]

I'm running FreeBSD inside a VM that is providing the virtual disks backed
by several ZFS zvols on the host. I want to run ZFS on the VM itself too
for simplified management and backup purposes.

The question I have is on the VM guest, do I really need to run a raid-z or
mirror or can I just use a single virtual disk (or even a stripe)? Given
that the underlying storage for the virtual disk is a zvol on a raid-z
there should not really be too much worry for data corruption, I would
think. It would be equivalent to using a hardware raid for each component
of my zfs pool.

Opinions? Preferably well-reasoned ones. :)