Different beasts but I have a MM bridge in my Blackmachine and a CS set in my rosewood necked Cu24.
The MM is kind of surgical, although that may have a lot to do with the guitar it's in too. Cleans aren't great unless you have a fantastic clean channel on your amp.
The CS set, as recommended by Tim at BKP as a more direct replacement, rule. Especially the bridge which is slightly cooler but a lot more rounded and less wooly then the HFS. I didn't mind the VB but the CS is a definite step up. The set is really versatile - I mainly do the metal thing but they will take anything that you throw at them and do it well. I was mildly disappointed with how my CuRo sounded, stock, but the CS set really cheered me up!
I'm just sorry that I can't compare them in the same guitar.
If you do order from BKP, make sure to tell them if you're using the PRS 5 way rotary switch as this affects how they load the magnets in the neck pickup.