I was an early adopter of the HD plasma TV, and although it's performance has stood the test of time, it only has 1 HDMI socket on the back. For years it wasn't a problem, but now I have blu-ray, xbox 360 and Sky+ HD, all of which use the HDMI connection.
This 3 port switch is exactly what I needed, enabling all three gadgets to share the 1 HDMI socket on the TV.
However, as it's name suggests it has to be 'switched', but the switching is only automatic if you turn the connected devices on and off at the mains. If you leave them on standby (as most people do, especially the Sky+ box) it can't auto-detect which one you're using, so therefore has to be switched manually using the button on the top.
Having to switch manually is not the end of the world, but the fixed lead into the switch is only 50cm long, so not quite long enough to trail under the TV cabinet to keep it hidden but handy. Therefore, I find myself having to reach around the back of the TV to grab the switch and press the button.
It'll certainly do until I upgrade my TV again, to one with more HDMI sockets!