Zear, I'm not 100% sure, but I don't think it is the shielding on the Presence that is different than GR, rather it is less conductors.
I've also owned and demoed Synergistic Resolution Ref. and Absolute Refs. the active shielding does make for a quieter cable, but not necessarily a better cable. The quietness/blackness of a cable is only one aspect of what makes a cable sound the way it does. There are so many variables in a cable, that to put too much emphasis on one aspect of it's design is fruitless.
I've also owned and demoed Synergistic Resolution Ref. and Absolute Refs. the active shielding does make for a quieter cable, but not necessarily a better cable. The quietness/blackness of a cable is only one aspect of what makes a cable sound the way it does. There are so many variables in a cable, that to put too much emphasis on one aspect of it's design is fruitless.