1. Performance and Scalability: Express Gateway is built on top of Node.js, which is known for its lightweight and efficient nature, offering high performance and scalability. On the other hand, Zuul is built on top of the Java Virtual Machine (JVM), which can be resource-intensive and may not be as performant or scalable as Express Gateway in certain scenarios.

2. Configuration and Customization: Express Gateway allows for a flexible and customizable configuration through a declarative YAML-based syntax. It provides a wide range of plugins and middleware options, making it easier to extend and customize the gateway's functionality according to specific requirements. In contrast, Zuul's configuration is typically done through a properties file or code-based configuration, which may require additional development effort for customization.

3. Service Discovery and Load Balancing: Express Gateway has built-in support for service discovery using popular tools like Consul, enabling automatic route resolution to backend services. It also supports various load balancing algorithms out of the box, such as round-robin, least connections, and IP hash. In comparison, while Zuul can utilize service discovery and load balancing through third-party plugins or libraries, it doesn't offer native support for these features.

4. Security and Authorization: Express Gateway provides granular security and authorization capabilities through its built-in plugins, such as JWT authentication, rate limiting, and OAuth support. It also integrates well with authentication providers like Auth0 and Keycloak. Zuul, on the other hand, relies on Spring Security for security and access control, which provides similar functionality but may require more configuration and development effort to achieve the same level of granularity.

5. Monitoring and Analytics: Express Gateway provides out-of-the-box integration with popular monitoring and analytics tools like Prometheus and Grafana, offering real-time insights into API traffic, performance metrics, and error tracking. In contrast, Zuul may require additional configuration and setup to enable similar monitoring and analytics capabilities.

6. Ecosystem and Community: Express Gateway has a growing ecosystem of plugins and extensions contributed by the community, providing additional features and integrations. It also has an active community of developers and contributors that actively support and improve the gateway. While Zuul also has a vibrant community due to its adoption within the Spring ecosystem, it may not have the same level of plugin availability and community support as Express Gateway.

In Summary, Express Gateway and Zuul differ in terms of performance, configuration/customization options, service discovery/load balancing support, security/authorization capabilities, monitoring/analytics integrations, and ecosystem/community support. These differences should be considered when choosing an API gateway solution based on specific requirements and preferences.