Kwm and khd (kwm does layouting, khd sets up keyboard shortcuts) are not the easiest to configure, and kwm can be extremely complex, but for me it's been the best window manager for Mac OS I've been able to find. I just wish that performance was better, and that it handled corner cases like small dialogs better.
Doesn't hold a candle to the ones available for Linux, but I blame Apple for that more than I blame the developers.
This tool reduces my cognitive load.
It's strange that a company focused on good design and ease of use is beholden to ancient window management traditions such as manually dragging every single window into the dimensions you want. When you open and close terminal windows to various servers dozens of times a day, need a window open on the side with a site showing documentation on this or that, it just doesn't make sense to waste time doing something that could be automated.