Yesterday I went to three shops and couldn't get any 67mm CPL. Kenko so I got told is not that good. Hoya were 2 types one of them was Pro1. B+W I saw it too. I was unable to decide which one is good for my Nikon 16-85mm.
So I will search here for more infos which my help me to get a clue which CPL.
Make sure you get one that is multi-coated! If you come across a Promaster, they have a coating called Repellamax which is excellent.
I just informed that the site has moved (see my quote of fotojack) and that I read something but didn't say anything about rules.