What's the best way to convert HTML to PDF in 2018?
medium.com
medium.com
FetchPDFs focus is on the template designer, which can be linked to or embedded to allow customisation of your outputs at scale (e.g. if you need to provide all of your users with the ability to customise their PDF outputs from your service).
YMMV.
It does seem like htmldoc doesn't support CSS which is going to be a blocker for a lot of people.
Pandoc is definitely worth considering but I didn't include it as I believe it just delegates it's PDF rendering to a configurable engine like LaTeX, weasyprint or wkhtmltopdf.
In my context I'm producing documents that need to be displayed in both contexts, so I steer clear of things that are primarily HTML.