DaveOwen: Thanks but the question I need answering is whether these switchers can cut smoothly, without any visual glitch at all, when you select a new source. It has to be able to cut between sources often and the audience should never see any rolling, breakup or momentary loss of picture stability. It has to look just as smooth as a video cutting from one shot to the next - as if was all part of the same video. I hope that's a bit clearer.
Welcome to the world of HDCP.
I have an HDMI splitter and distribution system in my house.
It works but not smoothly. Apparently because of HDCP negotiation (from my own research).