The Phantom 3 and Phantom 4 filters share the same diameter and thread pitch. The Phantom 4 has a longer lens, making them a bit longer than that of the Phantom 3. The filters can be interchanged, however the filters will not sit flush on the lens barrel.
Generally the choice of a specific filter is up to the user looking to obtain a specific look and feel. However, the chart below is a good starting point for those looking to see what filter works best in certain situations.