I have found an occasionally important problem with cheap HDMI cables. HDMI is supposed to have individual ground wires, one for each differential pair and one for the low-speed control signals, plus an outside shield that's connected to the connector shells at both ends. Most HDMI devices connect all these grounds together at both ends. Cheap HDMI cables take advantage of this practice by implementing a single foil shield that's only connected to the connector shells, and don't connect anything to the individual grounds. This works fine in most cases, particularly with short cables. However, you occasionally find a device that needs individual grounds and only works with some cables. That's lots of fun to debug until you find out about cheap cable contruction.
If only Bob Pease was still with us, he would have had plenty to say about cable (even though he wasn't a digital guy). He spent quite a bit of time trying to get the audiophiles to submit to a blind test involving standard and so called Oxygen free copper cable. They never would, though. And they wouldn't with this cable either, from what some of the "convinced" commenters had to say.