Puppeteer would indeed come close in rendering quality. Improvements of using my solution over puppeteer are:
1) I tweaked Chrome headless to have the fonts available to ensure that typography renders as it should. Even emojis work!
2) you don't need to worry about installing and maintaining puppeteer and Chrome headless into your own infra
3) I didn't really make this very clear on my landing page so far, but I'll provide support to clients that have issues getting a certain document to render exactly like they want.
4) Not really a benefit yet since I wanted to launch with the MVP but soon I'll offer several options in the API that puppeteer itself doesn't offer such as multi-document PDFs, automated clickable terms of content for longer documents, etc.