I won't submit a vote, but here are my thoughts:
I think it's a bit unfortunate that AKG calls all those capsule versions (brass, nylon linear, nylon with treble boost) "CK-12." They're all fine capsules but for very different applications.
The brass version has a certain kind of magic that makes it an impressive capsule for a vocal mic, preferably with tube electronics.
The linear nylon versions sound very different. Less exciting perhaps but very good for a utility kind of mic, preferably with solid state electronics. The current version is not identical with the original version, but still very nice (I compared my C414 EB P48 to a current C414 XLS).
Later on AKG added another nylon version with a treble boost. It was meant to capture the sound of the old brass version. Well, it doesn't. It sounds good, but it just doesen't have the same magic.
Bottom line, AKG's current capsules are still well made and high quality, but if you need to replace a brass CK-12, I'd recommend Tim Campbell's.