KVM with ZFS

Hey guys, just wondering if anyone has had experience with running a KVM image on top of a ZFS file system. The reason I ask is I noticed some horrible performance with using btrfs and later found this http://www.linux-kvm.org/page/Tuning_KVM which states at the bottom of the page:

Don't use the linux filesystem btrfs on the host for the image files. It will result in low IO performance. The kvm guest may even freeze when high IO traffic is done on the guest.

So I thought I would see if anyone could tell me whether or not I'll take a big performance hit using ZFS as well.