Bindings sound great. They look great. Hook the wrong one up or miss a hookup and you’re debugging a bizarre sort of behavior without benefit of source code for days. The binding protocol between outline view and tree controller is awful and totally opaque – if you want to add colored rows or something you’re out of luck.

I consider bindings to be a nice idea (and in things like VisualWorks they rock), but without source code and better debugging tools, they are a total time hoover.