Mac user since 1987, Lisa user before.

Mac windows do snap together when they're close to each other or the edge of the screen.

You can option double-click any corner to make the window fill the screen without going into fullscreen mode.

You can double-click any edge or corner to make it expand to the edge.

Hold down option and mouse over the green traffic light, and you get the option to fill the left or right half of the screen.

The main issues for me are:

1. changing monitor configurations destroys my arrangement

2. the menu bar, on large screens, is too far away — it needs to be closer to where I'm actively working