This is a very interesting thread, and one I have been watching for a while so thought I would contribute my thoughts.
I have been using Twinmotion with Vectorworks for a while now and generally it works really well with the .C4D export. The Renderworks textures come through and although may need some adjustments and can be improved in Twinmotion. Then you can add trees, people, cars and furniture etc. If the Vectorworks model needs to be changed then simply modify it and re-export the .C4D export from VW. Then you can re-locate the new geometry in Twinmotion and all the Twinmotion work stays with added props, cameras and video sequences etc. Sure a Live Sync with Twinmotion like the one that just come out for Lumion would be amazing and I really hope its not too long before Mac users can have this workflow available too. Lumion and Twinmotion are very similar in many ways, and each has some unique features, but Twinmotion is cross platform, and the preview on a decent GPU is really awesome, and the renders take minutes not hours!
Anyway, I made a new video this weekend on Vectorworks Site Modelling and Twinmotion if you are interested. Please remember if you don't like the funky tunes you can turn the volume down! Twinmotion work starts at about 3:20. There is lots more VW/Twinmotion videos on the channel including a recent one made with Twinmotion themselves.:-