How much doctrinal unity you need to partner with someone depends on what you are partnering with them for. - Tim Keller
I once asked on FB during a rare Q&A by Keller pertaining to the workshop: Center Church: What do you need to compromise? I did not receive an answer.
Indirectly, after almost a year, I saw this in his Tweets.
Pros are expected. Cons have to do with fellowship quality.