1. Scalability: 3scale is designed as a full-fledged API management solution, providing scalability to handle a large number of APIs and API consumers. On the other hand, Zuul is a lightweight proxying solution focused on routing and filtering requests, which may limit its scalability in comparison.
2. Features: 3scale offers a comprehensive set of features such as access control, rate limiting, analytics, and developer portal. Conversely, Zuul primarily focuses on request routing, load balancing, and filtering without the extensive feature set of 3scale.
3. Integration: 3scale seamlessly integrates with various systems and platforms, enabling easy implementation with existing infrastructures. In contrast, Zuul may require more manual configuration and customization to integrate with different technologies due to its limited integration capabilities.
4. Support: 3scale typically provides dedicated support, service-level agreements (SLAs), and a support community to assist users with any issues or challenges they may encounter. In contrast, Zuul may have limited support options and resources available for users seeking assistance.
5. Deployment: 3scale offers deployment options in cloud environments, on-premises, or as a hybrid solution, providing flexibility to organizations with different deployment preferences. On the contrary, Zuul is usually deployed as part of the Netflix ecosystem, which may limit deployment choices for users outside of that environment.

In Summary, 3scale and Zuul differ in scalability, features, integration, support, and deployment options.