i don`t think you can tell the difference between the 2 as far as sound. one looks like an (rca-jack) like the jacks on a turntable, the other looks like a wire with 2 square heads on each end where as if you plug one end into your digi input then looked at the other end you would see a red light that will let you know that the cable is active. (they call this Light Pipe) now both are considered to be consumer standard because these type of digi hook ups are found on most consumer products. you can buy the cables at any radio shack. not only that, the pros wouldn`t consider using this method for recording. they use (aes-ebu) digi connections. however they will most likely use the consumer method for transferring music from 1 dat to another for example. like (classic) said there is no degredation in sound at all. what ever it sounds like on the initial machine, it will sound the same on the end machine. however i will not tell you not to use it for whatever reason you might want to use it for. if it sounds good to you, then go for it.
oh yea, since the gina24 carries both spdif coax and spdif optical you can only figure out which cable you will need by checking the digi connections on the equipment that you are going to be hooking it up to.