A while ago, I was involved in some tests relating to SnapMirror and documented portions of it here http://rajeev.name/blog/?s=snapmirror (external link).
However, I am wondering if folks have done similar work and are able to measure the SnapMirror rates that resulted from the exercise/effort. Without going into any environment specifics, a one liner like "VSM with De-dupe over a T1 link, we observed a rate of XX kbps" might be a useful stat to gather.