even though Qt might and wxwidgets might be better(wxwidgets is really more a wrapper to different gui backends), IMHO linux lacks a proper gui toolkit.

creating gui applications is much better in both windows in osx. Cocoa was a fairly well designed base api that gradually got improved. (yeah, there is a lot of valid criticism here too, but we're comparing it to gtk in this case)

We should build something that can gradually phase out GTK as was done with Carbon. If linux had a nice gui toolkit people would write more linux desktop applications.

Just my opinion. So feel free to completely disagree with it.