JollysFastVNC is, as its name implies, a fast Universal VNC client.

Watch the demo movie to get a feel for how fast it is.

Despite my insuccess with one of the early alphas in what regards international keyboard support, I have had a number of friends telling me it works OK for them (minus some minor quirks), and the developer (Patrick Stein) is very motivated towards ensuring that keyboard encoding issues are fixed once and for all, so this is likely to require close tracking.