Have I got anything useful (other than VLC)?
If you're talking about the basic F4M version (free), I don't think so. Theoretically, the F4M plugin could be used by programs other than QT, but I don't know of any that do. You could compare the F4M extensions in Safari's Installed Plug-ins window (Help menu) with VLC's codec list
to get an idea of the differences (mostly playlists etc.). Should you ever run into a Windows media issue where VLC is non-responsive, you could give the QT-F4M combo a shot.
If you're talking about any of the paid
F4M components, things are different. But then you'd also be talking something other than just playback:Flip4Mac WMV export components can be used with applications such as QuickTime 7 Pro, Final Cut Pro, Compressor, iMovie, Keynote, PowerPoint, among others, as well as within web browsers such as Safari, Firefox and Google Chrome.