The downside of running multiple computers can be how to operate them efficiently simultaneously. I personally use a 27″ iMac as my “brute” machine (12GB RAM, 1TB HDD), using it to drive photography archiving, video formatting and back ups of application libraries such as Mail folders and Evernote. Alongside I have a 13″ MacBook Pro that is lighting fast, due in part to a 250GB SSD which ironically needs to be “space managed.” For many years I had two keyboards, a Magic Trackpad and a mouse to control both machines, until I had the need to load a keyboard to another household system.
That’s when I found Teleport by Abyssoft. This is a great application that allows you, through a choice of keystrokes, to swop control from one system to the next. You can use multiple screens in any configuration as the application can visualize this for you in it’s “configure” settings.
Unfortunately this great application can break if the circumstances change that link the macs such as logging off or even going in to sleep mode. I have found, through trial and error, that quit the application on the source mac (where the keyboard is attached to) and then relaunching it, will re-establish the connection and you should be good to go. Occasionally relaunching on the other mac(s) by be necessary too, but rarely in my experience to date.