Cokin or kood filters ND and Polarising

I am looking to buy some filters for my 3 lens (35mm, 90mm, 18-200mm) on a D300

I thought I would go with a square system though I probably wont uses all the filters n all the lenses.

Doubt I will use a grad ND on the macro lens.

and I think I will only use them occasionally - I say that now but who knows

ND2, ND4, ND8 solid & Grad (6 filters in total)

blue grad & red grad (2 filters in total)

and a POLARIZER (Circular)

the Cokin polarizer is about  twice the price of the Kood.

would I actually see a difference or would I be wasting my money on the Cokin?

the LEE system is expensive!

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Thanks