I use one of these to control 2 PCs and one laptop with a single keyboard and mouse. It could actually run a 4th machine off the same keyboard and mouse if I wanted to cram another into my workspace.
Sharing two 4k monitors between the three as well, though the screens have nothing to do with the switch controlling keyboard and mouse.
Used some double sided tape to attach the little controller switch to the top of the docking station connecting my laptop to the displays and network as it’s a light little thing that would fly all over the place otherwise. Been using the same one for over 2 years now and it’s been working great!
Tried some more expensive solutions in an attempt to tie my monitors and network together along with the kbm and everything I tried had some kind of unacceptable compromise, like bad video quality.
I have a shield connected to a projector through an av receiver. I love the setup for its audio visual fidelity, but I love the simplicity of operation almost as much. The shield remote turns everything on and off and handles all my streaming services + steam link flawlessly. Wonderful user experience.