I use bspwm, which has a very simple design and follows the unix philosophy quite nicely. A single daemon process which manages windows, and all configuration is done with the shell via the `bspc` command, which talks to the daemon over a socket. A separate daemon (sxhkd) is used for keybindings, and the configuration for sxhkd is just a map of keybindings (including mouse buttons) to shell commands, with a very simple DSL to allow groups of commands, and the use of the cursor position. Example from my configuration:

    alt + {Left,Down,Up,Right,h,j,k,l}
        bspc window --focus {left,down,up,right,left,down,up,right}

    {alt,super} + Tab	
        bspc {window,monitor} --focus next
    
    alt + super + {Left,Down,Up,Right}
        bspc window --swap {left,down,up,right}

    super + {Left,Down,Up,Right}
        bspc window --edge {left,down,up,right} push
    
    super + shift + {Left,Down,Up,Right}
        bspc window --edge {right,up,down,left} pull

    super + q
        bspc window --kill

Worth noting that bspwm treats monitors individually when using window commands, so you need a separate set to handle windows on diff monitors (unless using Xinerama).

I've no idea whether it works on OSX though. 2bwm seems to be popular among OSX users, but I've not tried it.