DOpus4 was and still is the best on the Amiga. Now that it is open source someone should port it to OS4. They have had since at lease as far back as 2003 to work on a port so it is odd that no one has bothered. The developer of the open source version even mentioned AOS4 on his DOpus 4 site, but sadly he stopped work on the open source project in 2004.