if you are doing html to pdf, you might also need the ability to merge. a few more features and you're better of with a commercial solution.

Merge what?

I assume combining 2+ documents. For example, attaching a cover page with document owner/version control/lifecycle information to an existing PDF.

	▲	crazygringo a day ago \| parent [-]
		That's the easiest thing in the world with free software. One way is to install poppler-utils and use pdfunite. There are many other open-source packages you can use as well.