Which VNC Software Is Best?

Futurepower(R) writes "Which VNC software do you think is best, and why? There are several free programs, for example, TightVNC, RealVNC, UltraVNC, and TridiaVNC. Or, is it better to pay for VNC software, like Tridia VNC Pro or Radmin? Which is fastest, most secure, and the least hassle? Which has video resolution scaling of the remote desktop?"