What do you like best?
Speed of report development is amazing. Once we learned all the tricks, we were rolling out production reports in a day. Embedding them into our web apps is easy using either the API or URL's.
Graphing options are extensive and visually engaging. Once configured, ease of use and administration is excellent.
What do you dislike?
Some things are better done in the web based "Web Report Studio" and others are better done in the "JReport Designer" application. My personal preference is the web based interface, and I wish all functionality from the application were available in both places. A few inconsistencies in how you do things between tools makes it a bit confusing to switch between them. It appears that the web interface is improving with each release, and soon there will be very little need for me to use the application for developing reports at all.
Recommendations to others considering the product
Evaluate the competition, and discover the value of JReports. We found it a very complete and cost effective solution.
What business problems are you solving with the product? What benefits have you realized?
We have implemented extensive executive level reporting using JReports, giving our executive team a detail level view of the health of the company. It has helped us track key performance metrics and implement business processes to address the issues previously undiscovered.