I love the PK neck. Great pickup, and I'd choose it over the CS. Actually, I have - my main guitar used to have C-Pig/C-S, now its a PK set that I got for one of my lesser guitars. The decreased lows and slight taming of the low mid snarl of the c-pig, and gain reduction, were worth it for the ludicrous tightness, clarity and un-compressedness of the PK (for such a powerfull pickup, its a BIG harmonic-rich sound that comes from a medium-metal wind + big magnets (3 of them, I believe) giving a tonne of gain but you can still hear the actual chime of your strings because its not so compressed).
Neck wise, I thought the CS was it for me when I first heard it, and for about a year after that. Bell-like cleans, fluid, smooth, middy shred - what more do you want from a neck pickup? But the PK outdid it. Its thicker and fuller, sharper and clearer, notes are more defined, but not razor-like, they still flow very well, its much more aggressive (but not harsh or brittle at all) and still backs off very well, its cleans still have a chime to them, but they have a more low mid than the CS and are more balanced (more of a broader mid hump than the CS) and its generally utterly awesome. Its the only ceramic neck that I (knowingly) like, and it my favourite neck, too - thats gotta say something.