Seen at two customers using JasperReports. They switched from JasperReports to vanilla generation of RTF (just a lot of print statements) since they could not generate editable letters in JasperReports.
Their problem is that all objects in an exported RTF document are frames. Frames always stay at the same place and do not influence surrounding frames.
However, if you generate a letter (for instance a loan application), a user might want to adapt some things, change the amount, add an extra legal condition of three lines, etc.
This is not practically possible. If could be largely solved if the RTF exporter would use tables instead of frames.
Tables influence each other on a page.