PDF::Reuse is an absolute gem of a Perl Package. A little tricky to make and install (more so the Barcode package(s)) but very much worth it.
I used it at the core of a corporate Merge Data and Forms suite written primarily as a browser delivered PHP application. The PHP interface allows the user to build quite complex print job definitions (including data sourcing etc) and save these (ultimately) as a Perl Hash of job parameters that is included into the processing script at runtime.
This suite allowed our public sector organisation to move away from dependency on highly programatically controlled Xerox DJDE based scripted printing to a more open Data with Forms application.
This meant we could give more control on development and maintenance output documentation to our end-user department and printing room staff - freeing programming time (and expense) for other things.
Could not have done it without PDF::Reuse - simple, reliable and powerful. It is its power to create complex and varied printed output using a few, easy to master commands that gave it an overall 5 in my assessment. I found teething problems getting PDF background forms to work were best overcome by producing my background PDF using CutePDF writer.