I have just tested camera tracking for the first time and done an extremely simple (and bad) animation of a spider crawling across a desk composited over live footage: https://www.youtube.com/watch?v=Ag9ZrVKBFKM
The scene was automatically set up for me after tracking, Blender added a shadow catcher etc.
My question is, should I render it all out as separate passes and composite/ post process in the video editor or is it better to composite before rendering?