PDFpen 7.1 got a nice update with some bug fixes and new features, including formatting options for page numbering and custom stamps. For me, the big new feature is the ability to auto-deskew when performing optical character recognition. Sadly, some of the people I work with aren't anal-retentive nerds and they often send me scanned documents that are more skewed than a cable news program.
With version 7.1, PDFpen will now perform the OCR and then straighten the page using the OCR'd text as a baseline. That means when you go to highlight later, everything lines up, just right. This made me so happy that I made a video.