Author here. I actually started this project after buying Divvy. Divvy has many more features but I could never set it up just right. In particular I found no way to use the grid feature without the mouse (other than assigning shortcuts to pre-defined layouts). So I scratched my own itch and created Keypad Layout as a simple no-frills replacement that works exactly the way I want it to.
I own Magnet, Moom, Cinch and a few others. I always end up abandoning because the powerful keyboard features get in the way when you're in an actual workflow, and the basic ones make me reach for the mouse.
Yes, I ended up using pre-defined shortcuts for common areas. It seemed like a massive downer after paying money for it, but in the end covered 95% of my use-cases acceptably.
I have a 4k monitor and Divvy is a godsend for setting up the monitor as a 6x6 grid which I can then split with either the numpad keys or the 2x3 stacked control keys which mirror the layouts.