Infraworks 360 is incredibly good at producing multiple preliminary layouts and modifying them very quickly to the required road and highway standards.
We have recently used it in anger for the first time and produced over 30 proposals with in a couple of weeks, compared to 5 proposals created in 2D by another office that took them 8 weeks! This was for a £100m project .
You can then very easily export into C3D and do your detailed design, (and re-import into IW360 if you want). You can also work backwards and forwards with 3DS Max & Revit to improve the visual look of IW360 models.
While it doesn't give visuals to the standard of 3DS Max, the videos etc that you can produce are still very good and in time these will improve. We have already had very good feedback over a couple of videos we have produced. They also have the benefit of being created in a fraction of the time it takes in 3DS Max, and as you modify the IW360 model, the video automatically updates.
Sharing your models with others to keep them updated is also very quick and easy, and if they are running the free version it's almost instant.
Management love it, as they can see options created very quickly and modified very quickly. The savings this will make has huge potential!
I think if you dismiss IW360 you will be missing the boat. It looks like in the next few years IW360 will be increasingly linked with/into C3D, and at some point they will become one product.