I first purchased PDFpenPro back in 2013, at version 6.0.5. I never did see any advantage it had over Preview and Acrobat, but I stuck with it, all through the (paid) updates.I appreciate the feedback, but, no, I'm not sending sensitive financial documents to a company that sells fundamentally dysfunctional, buggy software without any warranty and then wasting more time and effort helping them debug it. I'm cutting my losses at eighty bucks and a bunch of wasted hours on my part and that of a critical financial partner. Unacceptable. I'm not an Adobe fan, but the next time I need to deal with PDFs like this, I expect I'll be using Acrobat.
By the time September 2016 rolled around, the next (paid) update was version 8.x, which I purchased in spite of never really using the program. I just felt it was good backup, in case it offered features that my other apps did not have.
Finally April 2017 came around and yet another paid update, just seven months from the last one! After encountering several bugs in the program, and never having used it for anything, I gave up. I still have yet to hear about a single virtue it has over Preview or Acrobat DC.
By the way, for light use, Adobe Acrobat Reader DC might be sufficient. I keep a copy for myself, so I can be familiar enough with it to recommend it to my average client.