keyclone does pretty much everything that the other programs promise to do, except that it does everything i need right out of the 'box' whereas multibox, synergy, etc, have quite a lot of setup and config and even programming before things are tailored to your specific needs. keyclone requires very little setup aside from defining keys you dont want passed, round robin keys (for things like alternating which characters cast frost nova, fear, etc) and entering the network IP's you want to clone to. ive never done any programming and my knowledge of system stuff is limited to whatever i need to know to play games efficiently, and it still took me literally 20 seconds to set keyclone up. i almost gave up on synergy just reading the documentation.

i think its still worthwhile looking into programs like Synergy in combination with KC. i still use a KVM switch and a cheap mouse/keyboard which i have set up to input only to the PC the switch has selected. i can hotkey between screens with 0 delay and input without broadcasting, and then switch back to my main machine when i want to send keystrokes to all PC's. its also really nice to just grab the second mouse to target aoe's or sync mouseclicks for accepting quests etc.