Actuate BIRT - open source that's worth a look
- The report outputs can vary across different types such as HTML, PDF, and Excel
- Their open source offering is very sufficient
- There are great boards and blogs for developers and engineers to expand and use their features.
- The people from the company that I've worked with are professional and courteous.
Cons
- The report designer can be unstable at times.
- The reporting engine tends to have memory leaks with certain types of massive-data reporting.
- The report graphics don't have the sexiest appeal (e.g. Glossy feel, animated output)
- Some extensibility is extremely difficult to get to without purchasing a license (e.g. Setting a simple flag so that HTML outputs in compressed mode requires either creating your own emitter or going the paid route)