This isn't new, but a lot of folks don't seem to realize just how bad PDFs are. Remember when we told people to send us PDFs instead of Word documents because we thought PDFs were "safe"? Boy, were we wrong. OK, we weren't wrong, but times (and threats) have certainly changed. Now, with the XML-based Office file formats and the proliferation of PDF malware, I'm much more leery of PDFs than DOCX files. The PDF specs are part of the problem, and the implementations of PDF readers are another part of the problem- the specs allow for things like embedded executables, and the implementations are buggy. If you haven't read about these issues, check out the articles below:
As I said, Gpdf is not perfect, but it is a step forward. Which is the right direction.