You cant connect a R30 000 Blue-ray player to a R150 000 Amplifier with a R170 cable...
It's against the audiophile code of ethics... if its expensive, it works better.
I think once a cable has sufficiently thick copper strands to cope with the digital signal throughput required... and good quality contact heads... the rest is "Home theater penis size".
Agreed, in the analogue cables, signal degradation per meter is a factor. So you'd need extreme low resistance wire, thick as hell, plenty strands, oxygen free this and that... etc etc etc.
But with the digital cables... you got cheap, decent and overpriced.
You want a cable that has the gold contacts, thick enough to handle the digital signal throughput and well insulated to prevent interference. The cable must also be well made... you don't want the joints by the head to start coming loose.
The standard issue cables you'll get with a cheap DVD or Blu-ray players are good enough, but they'll get crusty around the heads after a few short months.
Ellies is cheap cable... if you're using a HDMI interface for both audio and video between two High-end components, you might notice a slight degradation in sound quality since its prone to interference coz of the thin individual strands.
Labgear is good cable... thick enough, gold contacts so you don't "lose quality" if your appliance has gold contacts too. and its well made.
I bought a 5m HDMI cable off the shelf from STAX at R370. That is not a bad price...
I don't see the justification in paying more for a digital cable... really.