Fast switching KVM?

Hi,

I'm working on site so I need a fast switching KVM in case someone comes in my office and I'm on J2 PC.

I currently have an entry level Tesmart which is OK but it takes 6 seconds to switch which seems like an eternity when a colleague comes in my office to show me something on my screen.

Any suggestions before I buy a new one?
It needs to be able to switch from the keyboard and accept HDMI.