I'm sorry, but I just have to react to what is to me an obviously unfair comment.

It is quite possible the user who wrote "careful with this" experienced a hang, but I have not had problems saving PDFClerk documents. The rest of his claims about the software are nonsense though: PDFClerk offers several different PDF export options, and the option to save intermediate results in its own file format allows for much needed flexibility. It's a plus, not a minus. I'm never forced to use a particular format. I can pick and choose as the situation requires, it being equally easy to use either format. And, just like with the earlier commentators, I've been met with excellent customer support: fast and efficient.
I once was working on a pdf using PDFClerk and needed some functionality that was not there and contacted the developer. Within a couple of days he had added it.
The developer is obviously eager to help. Make sure to read the developer's reply to the previous commentator's claims, and you'll see that even his claim of flatly being denied a refund is not true. Based on my previous experiences with this developer, I have no doubts his comments reflect what actually happened. There are not many PDF editors around that offer great functionality at a great price, but this is certainly one of them, and I have a hard time imagining anyone being unfairly treated by this developer.

PDFClerk has saved me a lot of time in many occasions and I feel fortunate being able to use this product that continues to grow from strength to strength with such an engaged and supportive developper behind it.