I use the donationware app named Spectacle, others in my office use both Divvy and Moom.
I prefer Spectacle, and my wants/needs are simple. I can center/resize windows, move windows between monitors or within a Space, and make other changes with keyboard shortcuts. Customizable keyboard shortcuts, too.
And, FWIW, I also added a Keyboard Shortcut for the Finder Command "Zoom" to Control-Z in System Preferences. I'm a happy camper.