Earlier quoted context omitted.
That's just patently untrue: either GTk or Qt would work perfectly. I don't see why the desktop environment would matter--the program doesn't have to (and probably shouldn't) care whether I'm on Gnome or KDE or Unity. Moreover, all the popular environments support both GTk and Qt fairly well, and both are cross-platform, so you would actually be supporting more users than with a Mac OS-only program. Really, fragmenta…
> Moreover, all the popular environments support both GTk and Qt fairly well, and both are cross-platform, so you would actually be supporting more users than with a Mac OS-only program. By that logic Windows should be first since it has the most users. Also, are you sure that the installed base of Gtk+ or Qt (or both) is greater than the installed base of OS X?
Installed base is irrelevant if you include the libraries or statically link. You'll bloat your download a few MB, but it's manageable.