WinVNC vs. KVM Extender?

systmc asks: "I'm trying to decide between using WinVNC or a KVM extender at a customer's site. I'd like to use WinVNC but I'm concerned about it's CPU usage on a WinNT system (with an inactive client connected CPU usage was at around 8%, even with Raw encoding. PCAnywhere was about 0.5%). Does anyone have experience tweaking VNC? If hardware winds up being necessary, what KVM Extender would you recommend?"