Probably an unpopular opinion here, but I do not understand why people prefer tiling window managers. I prefer to have lots of windows open, and being able to position them how I want with the size I want greatly increases my productivity. Tiling window managers makes you conform to their way of working.
It recognizes apps that I have open and I wrote an algorithm to place them on the screen the way I want.
It also creates what I call scenes, which allows me to select from couple different dynamic arrangements of windows depending on what I work on.
I can also able to instantly decide what windows are on both monitors by having a simple script when I select a desktop and it is being brought to primary monitor and contents of primary monitor is pushed to secondary monitor. By pressing two key shortcuts in short succession I can almost instantly set any arbitrary windows on both monitors without moving my mouse.
Now, this would be difficult to organize on another WM, but is a breeze on i3.