I'm not so sure: the simplicity of the concept is nice but is-it really simple/nice to use?

I imagine that you could get lost quite easily in an infinite plane, so you'd need to be able to zoom out to find your windows but if you have too many windows opened then you have to zoom out so much than it's becoming hard to see which windows is what..

Workspaces seems a better way to organize your windows (even though it can also be difficult to find the workspace which contain the window you want).