I've been using Acrobat since Version 3 and PitStop Pro since Version 4, and finally there is a version worthy of the money charged. I should note that I'm currently using Acrobat 6 Pro along with PitStop Pro 6 on Mac OS 10.2.8 machine with Dual 1.25 GHz processors and 2 GB of RAM. At least with the current setup that I have now the editing is reasonably fast and stable, on OS9 using Acrobat 5 Pro and PSP 5 on a 300 MHz machine was absolute torture, mostly because it was so slow and crash prone.
We have a hybrid workflow in our shop, but I have had to deal with PDF's due to some of our client's needs. The most annoying thing I can say about this version are the font follies, but as noted in the article that was not Enfocus's problem. But it is a real problem and can slow you down considerably. I am a fan of the action lists, I develop my own, it's not hard to do. I use the preflighting from Acrobat 6 more often only because it's easier to navigate to, but the really good preflighting is in PSP. I really haven't done much with the automation in this plug-in, but each one of my projects are unique, so that hasn't been exploited as much as I would like.
We have a copy of Version 4 for PC, but I haven't updated it since I do the majority of my work on Mac. I would be curious to know if the PC version is as stable as the OSX version.
The local Graphic Arts Guild in our area held a seminar last week concerning PDF production, and the speaker noted that he had tested a number of the other PDF editors available and found this one to be the best. I can't really argue against that, even the earlier versions got me out of jams for which I am grateful. Even though the price of entry is rather high, if you deal with PDF's everyday or are switching to a PDF workflow, this tool should be in your toolbox.