I'm porting a ColdFusion 8 application to Open BlueDragon and the app in question generates documents using both iText and PDFBox (which I posted about before), and also generates PDF files from HTML content using CFDOCUMENT. When compared with CF 8 I ran into some differences with CFDOCUMENT so I figured I'd post them here. In general everything just works, so this is more formatting issues than anything else.
1. Use Full URLs for Images and CSS
2. Tweak Your CSS as Needed
Because the underlying rendering engine differs between OpenBD and CF (not sure what CF is using, but OpenBD uses the amazing Flying Saucer project), you may see differences in the handling of CSS. None of the ones I ran into were biggies, and in many cases when I looked at the CSS being used, CF 8 wasn't doing what it was supposed to be doing so while the rendered output was what I wanted, it wasn't adhering properly to the CSS. One particular case I'll mention as an example--an h1 tag had a style of float:left in the CSS which wasn't being respected by CF 8, so when the document was generated in OpenBD there wasn't a break where I was expecting one. A quick change to float:none and all was well.
3. Empty Paragraphs Don't Count
I had some instances of <p> tags with CSS applied that were being used as spacers, to generate horizontal rules using a border style on the paragraph, etc. but these paragraph tags had nothing between them (e.g. <p class="spacer"><p>). If you don't have *something* in between the open and close paragraph tag the CSS doesn't seem to apply. Throwing a non-breaking space in (<p class="spacer"> </p>) worked great for me.
4. Font Differences
Remember that depending on OS platform and a bunch of other variables you may find differences in the fonts being output. In my case the CSS (which I got from someone else originally) was using Georgia as the main font and I don't have Georgia on my Ubuntu laptop, so the rendered output wasn't the same. Just make sure you have the fonts you want to use available. You can check the Fonts page in the OpenBD administrator to see how OpenBD hunts for fonts and to add your own font paths if necessary.
That's all I ran into with CFDOCUMENT on OpenBD--a few tweaks here and there and it's working fantastically well!