I have pc and macbook sitting next to each other, connected to the same ext monitor via active hdmi splitter. The pc I use mostly for debugging and testing the application I'm making. The mouse have a 2.4hz-dongle/bluetooth switch, as well as the keyboard, So I'm pretty much able to use the both systems at the same time, and when switching monitor to hdmi from pc, I don't even need to sync the browser since it's available on macbook to the right still. BTW switching mouse and keyboard can be bound to a single hotkey with their software, and switching takes ~1s, for me it makes working with 2 systems in parallel a seamless experience nowadays.
