Two or more screen are quite nice. However, to move a fullscreen window to another monitor you need to restore it,
grab it with your mouse, move it to the second screen and maximize it again. Others have a nice widescreen monitor that easily fits
two windows side by side. However, arraging two windows by mouse can be quite annoying.
Using Window Organizer you can arrange every focused window or move it to the next screen easily and quite by a shortcut without even touching the mouse.