So far I can’t see any difference between the VNC clients in performance or interoperability. Both are available as 64-bit native applications, and both have companion servers that use the common VNC protocol. The only technical advantage that TigerVNC has over TightVNC is that the former supports TLS encryption, although it’s not simple to get working and I haven’t tried to do it on Windows.
Since I began my foray into kvm this year I’ve been amazed at the performance improvements that spice provides over vnc. If kvm on Windows ever gets past the experimental stage a spice server will undoubtedly be part of that solution.
Big Note: At least up to the time I’m writing this the TigerVNC server service doesn’t seem to work on Windows 7 (it also doesn’t work with the latest TightVNC). The only way I’ve found to launch the server is as an individual user — just the way we’re used to doing on Linux. For now that means individually configuring the service for each user (again, just like on Linux), and if I want it to run in the background launching it by putting a link in the user’s Startup folder. I’m also struggling with the encryption settings, for now I’ve got encryption turned off but that’s obviously something I’m going to have to work on.