Metal vs paper filter for Chemex?
A paper filter is a true "filter" in that it basically only allows liquid to pass through. This means that you will have no sediment in your coffee, if that is a concern to you. Paper filters are absorbent though, so some of the flavor compounds of the coffee will be absorbed into the paper, and some other compounds as well (a chemical in coffee that causes a rise in cholesterol is absorbed by the paper). The paper can also lead to a papery flavor in your coffee.

Metal filters only filter out particulates of a certain size, so you will frequently end up with a layer of "sludge" at the bottom of your pot. Metal filters should be non-reactive though, so they will not add a flavor to your coffee and will allow everything extracted from your coffee to pass through. 

If cholesterol isn't a concern, I'd say try both and see which you like better.

Types of Coffee Filters

Coffee &amp; Cholesterol