The switch works really well - provided at least one source can supply power.
I use it to switch between a Mac laptop and a PC. The Mac happily powers the switch via HDMI, the PC does not. So when I remove the Mac, the switch goes to sleep and i get no video from the PC.
I am trying to source a 5VDC power pack or USB DC Power cable to supply the switch (no power pack was supplied, but the switch has a 3.5mm socket for external power).
Your millage may vary however, and this may not be an issue.