In Windows, Unity & Gnome, there are convenient keyboard shortcuts to manage windows, which at least I regularly use.
In Gnome and Windows:
Meta + Left/Right Arrow = Snap window left/right to fill half the screen.
Meta + Up Arrow= Maximise Window.
In Windows, Meta + Down Arrow:
If window is maximised, unmaximise.
If window is unmaximised, minimise.
Meta + H = Minimise Window.
In Unity(back in '14/'15 at least):
Ctrl+Alt+Number from Numpad=Window Snaps to corner/half or toggles maximisation.
The keyboard shortcuts currently available in UM use Alt+Fx which are much more cumbersome to use as they require a hand to leave its resting position from the keyboard.
I think it would be a great improvement if these defaults were replaced with shortcuts inspired from those mentioned previously. (I don’t know if they should be added as part of UM or as part of the DE)
In my opinion these are the ideal window management shortcuts:
Meta + Left/Right Arrow = Snap window Left/Right.
Meta + Up = Maximise Window.
Meta + Down = Always minimise, irrelative of context.
Ctrl + Alt + Numpad 1 = Snap bottom left quarter.
Ctrl + Alt + Numpad 2 = Snap Bottom Half.
Ctrl + Alt + Numpad 3 = Snap Bottom Right Corner.
Ctrl + Alt + Numpad 4 = Snap Left Half.
Ctrl + Alt + Numpad 5 = Toggle Maximise.
Ctrl + Alt + Numpad 6 = Snap Right Half.
Ctrl + Alt + Numpad 7 = Snap Top Left Quarter.
Ctrl + Alt + Numpad 8 = Snap Top Half.
Ctrl + Alt + Numpad 9 = Snap Top Right Quarter.