I cloned about 4GB worth the other night and it took at least 4 hours. If my math is correct, 12Mbit should take about 45 minutes to transfer that amount, one-way, so double that assuming 12Mbit is shared bandwidth for USB.

It could have been longer, in which case, 94cobra's numbers would be consistent with my own.

Still not an issue for me, but while we're on the topic...