I usually use cotton batting, as I don't much like the feel of polyester.
But I was given a top that had sashing and borders made of a very stretchy fabric, and I thought it would be difficult to pin and get it to stay flat.
So on the advice of a friend I tried fusible poly batting. I laid out the backing-batting-top sandwich on my double bed, and used an iron to press, according to the directions.
Not a bad result, I will say, and a lot easier to quilt.
Martha