When using the same audio format they will sound the same.
Now TOSLINK is immune to ground loops because it uses light and this has no common ground shared from system to system.
As long as you have no ground loop issues(more common from your cable box than any bluray player), either should sound the same.
HDMI is also very common and has lots of bandwidth, if your TV has audio return over HDMI(and your receiver has HDMI in) then you can have audio from other sources go back to the receiver without having to swap inputs on the receiver. Some setups also allow the receiver to be a HDMI switch by running all devices into the receiver and connecting it to the TV via HDMI.