GraniteDS has advantages over BlazeDS in licensing/support, JPA integration, remoting, real-time messaging, client frameworks, validation, and mobile support. It offers strong enterprise support and integration with Java frameworks. BlazeDS is best for small, open-source projects as it lacks some of GraniteDS' features and long-term support. GraniteDS also has an ambitious roadmap to incorporate new technologies while BlazeDS may encounter issues extending its capabilities.