An idea spawned by a recent grumble against recurrence of Mahayana threads and posts was to create an archive of previous comparative threads and other materials people can be pointed towards rather than clogging up the board and causing disruption. If you see others, perhaps they can be added here.
Here are some threads on comparison between Theravada and Zen meditation:
Thanks Dan, and thanks for your very useful input in some of those threads. As some of those discussions make clear, it is not really A versus B, but different ways of interpreting or implementing Dhamma/Dharma.