Pros
The incredible organizers and members who, despite Meetup's disconnection from their feedback and needs, manage to change lives with their work.
Cons
Instead of itemizing the instances in which there was a disconnect between Meetup's outward vision and the reality of their workplace, suffice it to say: If you care and want to have an impact, you will be isolated and convinced that 'you're [not communicating properly], or [not a team player], or [don't have realistic expectations],' and so on. Before you accept any offer from them, do yourself a favor and search LI for ex Meetup employees. See what they're up to and contrast their backgrounds with those who are in management positions. You can join Meetup and collect a paycheck, benefits and not care about what you're putting into the world - or you can search elsewhere for meaningful work. The choice is that stark.