105mm polarizer wanted: cirular or linear?

Hello!

I'm planning to buy the Lee filter holder system, along with the 105 mm front adopter ring for 105mm screw-in polarizers.

I've narrowed the 105mm filters to B+W 105mm MRC polarizers (Heliopans are even more expensive, cheaper alternatives don't have coatings) - they are available in circular and linear versions.

The question is: will I miss something - anything - if I choose the much cheaper linear version? I mean AF accuracy, picture quality, polarization effect, etc?

FYI, it's going to be used on a D90/D7000, and possibly on a D600 later.

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