These days 2 way backlinks are not that useful anymore. Google indexes only when they are one way. So if its 1:1 share its not really a very good idea. Infact it might impact adversely in the search engine ranking.
Depends on the other Websites. If I have a real relationship with them of friendly cooperation, then whether I'm going to get Google benefits out of it or not, I'd say it's a good idea. Usually traffic begets traffic, and if it's good traffic, I'm all for it.