My experience is that the jitter inherent to Toslink obscures any variation in cables if the cable has no flaws or defects. I hear break-in improvements and differences in other types of cables, but I have not experienced that with Toslink.
Bluejeans Cables says "we use a jacketed plastic optical fiber (POF) cable. While POF is in general rather lossy stuff compared to glass optical fiber, we prefer it for optical digital audio use because it's much more physically durable and because its aperture matches the spec for optical digital audio use, unlike glass fiber which is too small and must be used in bundles…In our own usage, we've tested these cables at lengths up to 50 feet and found them to perform perfectly even at those extended distances. We hand-cut and terminate each of these cables ourselves…"
I use their Toslink in my TV setup (nothing high end and the only thing that works for the consumer-level stuff there). It's been trouble free for years. Their cables are about $2 per foot.
