I have only ever used fibre sync cables (I have an Canon Ixus and dual S2000 strobes) and it works very well - never had any issues with reliability.
I can't compare it to electrical, since I've never tried it, but I do have one question for anyone who has used both. Since my S2000 strobes are triggered by my Ixus strobe, the time period between flashes is dictated by the time it takes my Ixus to recharge its flash. When I'm photographing things that move quickly I often get only one shot off, because the flash hasn't charged quickly enough for the second/third/fourth shot that I would have liked to take.
The S2000 "ready" lights blink away since they recharge in about a second... but they're useless to me until my Ixus has finished charging its flash... very frustrating. I can't help but think that with an electrical sync cable I could get a shot off every second or so.
Has anyone else noticed this?
Thanks