Benefits of WSO2 ESB

WSO2 ESB is a cloud enabled, 100% open source integration solution which is a  standards-based messaging engine that provides the value of messaging without writing code. Instead of having your heterogeneous enterprise applications and systems, which are using various standards and protocols, communicate point-to-point with each other, you can simply integrated with WSO2 ESB, which handles transforming and routing the messages to the appropriate destinations.

It also compromises of
- data integration capabilities, eliminating the need to use a separate data services server for your integration processes.
- managing long-running, stateful business processes.
- analytics capabilities for comprehensive monitoring
- message brokering capabilities that can be used for reliable messaging
- capabilities to run microservices for your integration flows.

Other than those key features, some benefits of having WSO2 ESB are,

• Enables communication among various heterogeneous applications and systems
• 100% open source, lightweight, and high performance
• Support for open standards such as REST, SOAP, WS-*
• Support for domain specific solutions (SAP, FIX, HL7)
• Support message format transformation 
• Supports message routing 
• Supports message enrichment
• 160+ Connectors (A ready made tool that can be used to connect to public web APIs) such as Salesforce, JIRA, Twitter, LDAP, Facebook and more)
• Supports wider range of integration scenarios, known as EIP patterns
• Having Scalable and extensible architecture
• Easy to configure and re-use, tooling support via Developer Studio, which is an eclipse based tool for artifact design
• Equipped with ESB analytics, for real time monitoring

Find more on WSO2 ESB from:
http://wso2.com/library/articles/2017/07/what-is-wso2-esb/