Digital Cables : Coax or Optical which is best?

and if one is better then why?
I've been told that coax digital cables are best for runs up to approximately 2 meters, and that optical cables are better for longer runs. I think the problem with optical cables is that it is difficult to obtain a perfect interface at the connections, resulting in signal reflections which interfere with the main signal.
The best designed and made cable is the best.

Happy Listening.