Galaxy was, from what I could gather, a cross platform toolkit that one would have to explicity program to. QuickTransit translates binaries compiled for one CPU instruction set to another instruction set at runtime. If it works as advertised, 3rd party devs wouldn't have to recompile and redistribute their apps initially (they could do so later if/when they are ready.
Trolltech makes a cross platform toolkit. They seem to be doing ok.
I too am wondering how the RDF will hold up when the audience starts flinging 'reality' at Steve on-stage.