Both digital cables send the same type of signal (& I would recomend either one to anybody because digital is the way to go). the coax does it with electricity (electrons, voltage, pulses of current if you will) & the fiber-optics cable does it with optics (with light, or photons). If you can keep the digital cable relatively free from sharp bends & too much winding... then go ahead go with the optics cable, it will be virtually untouchable by electromagnetic noise that may be around your components. If it will be wound quite a bit or have to round a few corners... then go with the coax cable, it isn't affected as much by the bending. If you wanna know why, I'll reply again.
I own a Logitech Z-5500 speaker system. I would like to add a digital cable to the system, but am confused between the two cables. What's the difference, if any? HELP!!