
It is Open-source and sponsored by Eclipse Foundation which accounts for credibility, this is number one. There are many features that make BIRT a powerful platform and highly popular among other BI & Reporting players, for example, Multi-pass aggregates, Templates, Flexible Charting wizards, XML as Data sources, and Libraries. With the latest BIRT 2.0, it now supports CSV output, HTML pagination & Table of Contents. Review collected by and hosted on G2.com.
The UI is still traditional and surely demands a revamp to enhance the User Experience, as the product should be a fit in all angles, performance, experience, features, robust & scalable, security, and ease-of-use. Apart from the UI part, I don't find anything else which needs to be optimized or changed as of now. But there is a scope of improvement always. Review collected by and hosted on G2.com.