What's your price range?
I tried a few toslink and coax cables a few months ago. I did not find a big difference between the a $25 glass toslink sold on eBay and a few sub-$250 cables in my system. It sounded exactly the same as the $75 WireWorld Supernova 3
The Audioquest Optilink 5 was the best of the three I tried, but it was also ~$450.
Seems to me that there was equal performance to be had at a lesser price with digital coax cables.
But, if you;ve got to use toslink, I suggest borrowing several different brands and price ranges from Fatwyre.com's lending library. They are extremely helpful, reputable, and have been in business for quite a long time. You only pay 10-15% of the cable's total values for a 14 day in-home trial with that amount applied to the sale if you buy from them. They sell deeply discounted used cables, also.
They are the only way to find out what works best in your system.