Am I the only one who hardly sees any value in window managers? About 99% of the time, I'm wanting only one window visible at a time, with others quickly accessible via cmd-tab and cmd=`.
I think it also depends what kind of development you do. Doing iOS dev, I am constantly flipping between XCode, Photoshop, Chrome, Tower, Simulator and a bunch of other tools which don't play well with the idea of being sequestered to individual areas of the monitor. When I do openFrameworks development, I have to add multiple virtual machines to the mix (Windows and Linux while running on OSX) for cross-compiling and testing.
I use two thunderbolt cinema displays and I still constantly run out of screen real estate so tools like these, though I've tried to use them, end up not fitting into how I work.
ymmv.