Out of your list I have only had and used one, the Nordost Silver Shadow.
This was a HUGE improvement over my old Monster Cable spdif but no real surprise there.
An even bigger upgrade was to a Nordost Heimdall 2 but now you are really up there in price.
What I think you could expect from the Silver Shadow though.
Much more detail, less grain, very fast and taut in the treble and mids, possibly a little lean in the bass. If your system is already lean probably not a good idea but if you are on the warmer side it could really pan out well.
This was a HUGE improvement over my old Monster Cable spdif but no real surprise there.
An even bigger upgrade was to a Nordost Heimdall 2 but now you are really up there in price.
What I think you could expect from the Silver Shadow though.
Much more detail, less grain, very fast and taut in the treble and mids, possibly a little lean in the bass. If your system is already lean probably not a good idea but if you are on the warmer side it could really pan out well.