I use a Toslink cable connecting a DVD player (as a transport) to a Bel Canto DAC1 so I cannot speak to any change in picture quality. I have used 3 different brands and two different lengths. When this was a "hot issue" the word was that 2 meter lengths helped with jitter reduction. I started with an Audio Research 1 meter, then went with a 2 meter XLO ERTOS, and then was told that I HAD to have the $180 2 meter Audio One Reference toslink. While the price was greatly different I did NOT hear a dime's worth of difference. However, the more expensive Audio One is very beautiful and it's connectors match and fit the DAC1 so well, I just had to keep it in place. A victim of fashion, no? In all seriousness, I would make sure the connectors fit well, that would seem to have to make a difference.
Charlie
Charlie