Not really. On Unix it was Motif vs OpenLook. On Windows it was MFC vs OWL. On Mac it was PowerPlant vs MacApp. And that was it really, and you could have stuck

Not really. On Unix it was Motif vs OpenLook. On Windows it was MFC vs OWL. On Mac it was PowerPlant vs MacApp. And that was it really, and you could have stuck with one for over a decade and never been short of work.