Despite an earlier reviewer's complaint that this app is overpriced because Skim and Preview have most of its features, I find that not to be the case. I use Skim and Preview a lot, but I use pdfPen when I need to add or delete or rearrange pdf pages in an extremely Mac-friendly environment. I use it a lot to insert or replace pdf pages I create in Word (using SAVE AS pdf). Also, when I fill in forms using Skim, the text disappears when I reopen the file with Preview or even Skim I believe, but the text filled in from pdfPen "sticks" no matter what app next opens the file. So, when I need to reuse filled-in forms, I rely on pdfPen. I also like that I was able to scan in my signature and save it as a pdfPen object for easily inserting (with resize capability to make it fit) into forms. I do find text creation and editing in pdfPen clunky compared with, say, Word, but I suspect that this is just the nature of pdf editors in general.