If the tractor you are looking at has a factory cab option, and you can swing it, get the factory cab, no comparison IMHO.
But, if you want to keep dry and warm, but enjoy the fresh air during the three other seasons, get the vinyl cab. A factory cab will add $6K to the price of a CUT.
You should go kick some tires, sit in a few, and see how you feel.
Hope I did not confuse you??