you have significantly less jitter in a good coax cable than in a good optical cable.
How so? The transmission channel (coax or optical) should have almost no effect on jitter. Jitter is introduced at the source of the signal, not in the medium through which it travels.
not to mention that coax cables are a hell of a lot more durable than optical cables.
True. I think you could easily break the end off of an optical cable, but it would take a lot more force to accomplish the same thing on a coax cable.
One thing that's nice about optical cable, though, is that you don't end up sharing your mic's signal ground with the noisy power ground of your recording devices. With coaxial cable, you run the risk that noise on your ground connection that is generated by the hard drives and tape drive motors in all of the rigs in the recording chain will end up on your mic signal ground. Any signal on mic ground might as well have been put on the mic signal itself if you are running unbalanced mic cables. As long as you're running balanced mic cables, then you should not have to worry so much. But get this:
If the main digital output from the source rig is optical, you don't have to worry at all about hard drive or tape motor noise ending up in your recording, no matter whether you are using balanced or unbalanced mic cables.
Ground noise has no way to couple back up the chain if the entrance to the chain is optical. Think about it. Optical cable has no ground connection, but coax does and in most rigs, it's part of the same ground structuire that goes in the shield connection to the mics.
So, if durability is your prime concern, go with coaxial. If noise immunity is your main concern, go with optical. Neither cable type will hurt the signal jitter.