The core literature retrieval function of Promethease makes an HTML report about your DNA. That most important feature is free. However there are several benefits to a paid report.
A report can be generated in approximately 5 minutes. Free reports take closer to 4 hours.
UI2 allows you to filter and re-sort your data while a zoomable live graph visualizes the relationships.
Promethease does not store your DNA data, nor is it ever shared with - or sold to - any external party. Links to your Promethease report are maintained for your convenience for 45 days from the day your report was run and then even those are permanently deleted.
A tag cloud visualization of the words in your report.
If you need to run many reports you might find it easier to prepare an .xml file which describes all the settings. See the exact syntax at Promethease/xml
The Promethease/Desktop version is currently lacking several features which were available in earlier release. These will probably be restored in a future release.