Hi Arjan,
We have a lot to cover here so let me see if I can answer your questions:
General:
1. Standard vs. Enterprise is explained here.
2. The completion event to create a PDF is a feature of the module which you can use without having to buy the source code. The source code is recommended if you want to alter or customize the code beyond what is already offered by the module.
3. There's a Dynamic Forms 3.x that's tentatively scheduled for early January. We are constantly looking for new ways to enhance the product and we will likely have another major DF release in 2010. You can see our UPgrade Policy here.
Technical:
1. If the text field will be hidden until the checkbox is checked, then it will remain blank until it is displayed. In the PDF, the token will not be replaced unless there's a value in it.
2. I think you got the CSS question...
3. I believe the minimum requirement for Dynamic Forms 3.1 is DNN 4.5 and should be no problem if you have that at least.
Thanks for your questions. Merry Christmas to you too!
Candace