There is also
PDF::Template which is a wrapper around
PDFLib which is both free and for-pay. The full PDFLib library has a pretty hefty license, but there is a PDFLite which has most features most people want, and it's free.
PDF::Template will work with both.
There has been some work done to make PDF::Template work with PDF::API2, but I haven't been able to successfully merge the changes that autrijus did into the mainline PDF::Template.
My criteria for good software:
- Does it work?
- Can someone else come in, make a change, and be reasonably certain no bugs were introduced?