I have been aiming for default settings which would render the site as you see it (screenshot style), but so that you can switch the settings to honor @media print CSS rules.

One of the biggest values I think this yet-another-PDF-service has is that if you open the print preview on a desktop Chrome, it should be really close to what the API renders. Should make debugging a bit easier.

The main use case is to render content generated by yourself, e.g. receipts and invoices, but I don't see a reason why it couldn't be used for rendering news or blog articles.