I and many people prefer digital coax over toslink. To my ears it sounds smoother, more refined. RTX converters are not always the best quality in toslink, there is an extra step in conversion for toslink, that isn't present in coax. IMO, you made the right decision-
We used a TosLink (Radio Shack, basic) until a dealer I like suggested that we'd prefer the sound using coax (Master from Audio Research, twice the price), so we connected the DVD player to the AVR using both, and switched the inputs. There is more sound using the coax, and the sound stage seems larger.