Any browser. The article has no detail but I suspect that doing it all with a web stack, or even just PDF output with wkhtmltopdf (or a similar solution) would be much quicker than writing a PDF generator from scratch.
I didn't have anything to lose. So if you have the chance to make it perfect (versus taking some off-the-shelf tool and possibly ending up with a PDF that isn't quite what you want), would you risk it?