PDF::API2 and PDF::Reuse are both great for generating pure pdf documents. Importing existing Javascript-enhanced forms and filling them out, that's another story.

PDF::Reuse has the ability to fill in forms, provided that the original PDF is not "optimized" or "linearized". The module documentation does describe a procedure for "concatenating the streams" of these documents, but it seems to be version-dependent.

CAM::PDF can read optimised/linearized documents but can only write single-streamed documents, so formatting might be tricky.

Both modules support PDF 1.4...more or less. CAM::PDF can change document permissions to some extent.

Text::PDF can produce forms but isn't great at processing them, and isn't well documented.

PDF::API2 took out form-fill back in 2003.