I do a lot of complex prints and use S3D exclusively as it allows me the highest control and the very complex multi-profile prints (different profles for different objects on the plate, multiple profiles per z-height for singel objects). I also save all my projects as factory files (all stl objects + all profiles 'frozen' in one archive file) so that I can tinker with the settings (or replace stl objects with newer versions) later on.

As such, yes it is worth it. If you do not need that kind of control then a freeware slicer will do fine as well.