The free ones are simply not going to be as polished and user friendly as some of the commercial programs.
I know of three free authoring programs that run under Windows, but there may be others: DVDStyler, GUIforDVDAuthor, and DVDAuthorGUI.
There are many commercial options. I’ve used TMPGenc Author in the past, and the older versions were not much more advanced than DVDStyler in my opinion. The latest version is TMPGenc Author 3 I believe, and includes a divx authoring option.
The one I use is DVDLab Pro. It is expensive for an authoring program, at least for one that isn’t at a purely professional level like Scenarist. Lab Pro is quite versatile though, and the help file that is included is one of the best I’ve seen.