I'm joining PDFs together to make one large document. When I do this with Process Manager, each PDF section has a bookmark, named with the title of the section it came from. This is very important to us, as we then use an Acrobat action to print a listing of the bookmarks to use as a contents page.
The combined PDF from Core has bookmarks too, but almost every section is titled ‘root’. As a contents list, this is no use to us.