I do use that, but I find that it's inconsistent. From what I can tell, it seems to toggle between the current size and the previous size -- which becomes problematic when using an external screen. Or perhaps that's just Finder -- it's hard to tell! Frustratingly, this matches the behaviour of alt-clicking (sorry, option-clicking) on the maximise button, and I really love being able to have two windows comfortably share a screen with no wasted space, aero-snap style.