ActionKit is a solution intended for huge organizations with in-house tech teams, whereas NationBuilder is accessible for all organizations, including those that can't afford or don't want to hassle of an additional, outside technical team. ActionKit supports email, events and donations and can be customized and integrated with your current website. But it is less full featured than NationBuilder, very expensive, and available only to progressive organizations. NationBuilder is far less expensive and available to anyone.