When done correctly both work well. For 'noisey' equipment I prefer to use optical (VDH / QED / CHORD) for others I use coax 'like' the powerbuys stuff. Why don't I use optical all the time? Well I have broken too many optical cables by misshandling so I use them only when necessary. Why don't I use coax all the time, well the optical isolation can be 'useful'. I think the cables 'like' the power buys coax are hard to beat for value and are pretty sturdy.
As with all of these things the devil is in the detail, what ever you do buy a quality cable fit for purpose. I prefer the thicker optical cables, preferabley made from well polished glass, and 75 ohm coax (quality one) with 75 ohm crimp plugs, stick to that and you will enjoy you fine kit.