[svandamme]

cast iron is the opposite of copper.. ok for a stew, to sear meat.. or for mixed use stove/oven.
but you just can't make sauces in it. It's to slow at changing temps.

Sauce pans have to be thin and copper.. temp control is key (Which you do not have with cast iron, or lesser extent steel), try making anything caramelize in cast iron..
takes forever to get hot and by the time you get the heat in it.. you can't turn it off again.. and it burns.

Falk is the cream of the crop , they are known by chefs world wide.. they are not cheap at all.