The most valuable features are the flexibility, ease of use for writing new test cases, the test plans, and the composition.
TestRail offers stable 24/7 operation with features like easy organization of test cases and useful integration with Confluence and JIRA. Its dashboard simplifies test runs and enhances management, though reporting flexibility is limited and custom reports are hard to create. API integration with automated tools can be cumbersome and Jenkins integration lacks seamlessness. Suggested improvements include adding traceability features, an issue management system, detailed configurations, and enhancing customer support and role-based access capabilities.