These devices are most definitely not always plain sailing and of course they all contravene the rules as set out by HDMI.org and DCP LLC!!!
Make sure the devices you are looking at will work with an HDCP encrypted signal - some of the low cost units we've looked at only work with non copyrighted material!!!
Also watch out for image shift and image degradation.
We all have our favoured solutions -
Media Factory - Vision HDMI to Component converter
Joe