[pxc]

I wouldn't characterize RDP as particularly fast or efficient.

If you're interested in a turnkey alternative, consider NoMachine.

If you are willing to play around with finicky stuff, Xpra and FreeNX easily outperformed RDP the last time I played with all this stuff (many years ago).

For Linux to Linux X Forwarding-based solutions give you a much better, local-like experience with Linux than you can get without paying many thousands of dollars for Terminal Services on Windows.