Why I can't quit Rectangle Pro
I use both Alfred and Keyboard Maestro fairly heavily. Both of them can move and resize windows. So why is Rectangle Pro still in my nerd cocktail? Because of these two features (screenshot from Rectangle’s settings):

These let me move and resize windows merely by pressing the configured shortcut and moving my mouse. This is so nice anytime I want a window size or location other the bog-standard ones (left-half, right-half, etc.). And I tend to want that a lot.
I got used to these shortcuts when I used i3 in Linux some years ago. I thought I’d have to say goodbye forever when I came back to the Mac, and I was so excited to rediscover them in Rectangle Pro.
I do wonder if I should give them up so I can stop running Rectangle Pro and simplify my rig. But for the time being, I’m still hooked.