I'm currently breaking in a pair of Grover 'SC' RCA analog ICs to replace my final 'S' pair (which were the gray ones that came after the white). While I no longer have the whites to compare it to, I definitely think the latest black 'SC' ICs are a step up from the 'S'.... While sonic differences are not dramatic, it seems to be a step toward more clarity and transparency without edginess.
FWIW, here's what I'm currently using...
Grover SC digital RCA IC - Squeezebox to Tact
Grover SC digital XLR IC - CD transport to Tact
Grover SC analog XLR ICs - Tact to amp
Grover SC analog RCA ICs - phono pre to Tact