At work I have to use a mac, it's a PITA to manage multiple non fullscreen windows on it. There is also a fair amount of screen estate lost per window.
Same with Windows, and Linux as they just copy Windows/Mac GUIs and never bother to finish them off. The problem is Raise-on-click, means you can USE overlapping windows, and drag and drop breaks. My theory is all GUIs are fundamentally stuck in the year they were first designed, so 1983 or so for Windows/Mac. Full screen, almost single tasking. RISC OS, being designed in 1986, is better, as a GUI.
At work I have to use a mac, it's a PITA to manage multiple non fullscreen windows on it. There is also a fair amount of screen estate lost per window.