I ran heroics most of yesterday using HotKeyNet (and five machines, only one copy of WoW per machine). It worked fine.

Vista 64 (x2), Vista 32 (x2), and WinXP (x1) all ran WoW fine.

For all the Vista naysayers out there, I can't say as I've been having all these problems that others are having. Sure, there are a few annoyances (like the popups requiring admin rights), but if I really wanted to I could just turn that off.