The most valuable features are the flexibility, ease of use for writing new test cases, the test plans, and the composition.
TestRail excels in test case organization with a robust API for integrating automated results, enhancing collaboration via Confluence and Jira. Known for stability, it simplifies test management with flexible reporting, though it lacks report customization and built-in defect management. Despite extensive API integration, ease of use with automation tools needs improvement. Customer support and pricing are noted for potential enhancement, with criticisms of slow responses and high costs.