zfs discuss - Sep 2008 - Any experience of bulk transfers with zfs send/receive ?

Hi

has anyone attempted transfers of large volume of data with zfs 
send/receive in a production environment.

I am seeing interest in zfs send/receive from people who have use rsync 
and similar technologies to copy data for DR purposes..but I have no 
idea of waht to expect so far as performance goes.

Thanks

Tim