I came here to suggest similar. I usually go with

    dd if=/dev/device | mbuffer to Ethernet to mbuffer dd of=/dev/device

(with some switches to select better block size and tell mbuffer to send/receive from a TCP socket)

If it's on a system with a fast enough processor I can save considerable time by compressing the stream over the network connection. This is particularly true when sending a relatively fresh installation where lots of the space on the source is zeroes.