Reporting on iSeries has come a long way. Traditionally, iSeries developers have to create reports using RLU, and then the RPG report program creates a spool file which the user then prints for his analysis. Its a normal sight to see users printing bulk print-outs from the spool file. Then the need came for sending the reports via email, and there are lot of tools now to convert spool files to PDFs to send the reports to others. Though these converted reports to PDF will suffice, they do not have a professional look; they may lack a company logo and there is no way to show different colors, charts, internationalization, bar codes, different fonts, etc.
Though you can buy a vendor product to do all those things, why not try Jasper Reports for free? With Jasper, you can achieve all these things and create a professional looking report with any formats you wish (PDF, Excel, rich text format, XML, and CSV). However, to use Jasper, you will have to use java, and integrate Jasper in your java programs. And moreover, you will have to write SQLs to generate the data for your report. Thus, it might not be the best idea to write a complex SQL to generate a report (for example, a purchase order report), in order to replace or imitate a legacy reporting RPG program. In that case, the conversion tools (converting spool to pdf) will be a better option.
So, consider using Jasper for any new reports or for any small-to-complicated reports where not more than 2 or 3 files are needed, or for any files with less data.