I like Divvy, too. I wonder how hard it would be to snap Divvy's GUI overlay onto these Linux tools. I frequently want to arrange windows not just in halves of the screen, but in thirds. I find that gets cumbersome with keyboard shortcuts alone.
i used divvy for one thing: making a window take up the full screen. on my laptop, i dont ever want to use half a screen... or at least i dont think i do. so dumb that i need to use divvy for this one thing. or maybe i dont? havent checked in forever.
It's rather limited - make window fill quarter/half screen, make window fill whole screen, move window to next monitor - but it's very easy to configure, and supports XQuartz windows.