The biggest problem is it's HTML based and WebKit based. Things that are trivial to do in a native PDF drawing library are a total pain because of the CSS factor.
Re:Wkhtmltopdf Considered Harmful
by pavel_lishin on Thursday July 19, 2018 @12:02PM
(#17567569)
Their conclusion is TLDR'd at the top, and that they have found something better.
> TL;DR: replace it with weasyprint.
The last line of the article is "We'll be keeping an eye on weasyprint." I'm pretty sure that means they don't think it's ready yet, and aren't using it yet. It looks promising but they don't directly test it against any of their complaints!
I, like many people in this thread, have used wkhtmltopdf for years and it works pretty well.
Wkhtmltopdf is far and away the best solution (at least in Ruby land) even if it is often painful to work with.