Having worked in the industry for some time, I have sat through multiple Audioquest "trainings". Most recently was one focusing on this very subject. The guy had several HDMI cables of varying quality/expense and attempted to demonstrate the audible differences between them by playing high res music from a MacBook Pro through a high end Marantz pre/pro and some B&W Diamonds. Needless to say, I heard no difference at all.
The most entertaining part of the presentation, though, involved their "high end" USB cables...