Which are the best online HTML to PDF converters ?

You can try following online websites:

www.htmlpdf.com
www.pdfcrowd.com
www.web2pdfconverter.com
www.html-to-pdf.net

To use the above sites, you may need to provide details like email and web URLs. You can try them one at a time and check the quality of pdf files they create.

According to me, pdfcrowd.com is the best available website which provides great features to convert webpages directly to pdf formats in just wink of seconds.

Pdfcrowd.com:
The following are the features offered by pdfcrowd.com:

• Provides the option to convert HTML to PDF and supports PHP, .NET, Java, Python, Ruby, and Node.js.
  
• Allows the webmasters to add a simple Save to PDF button on their site so that their visitors can save the site's web pages to PDF format in just single click.
  
• They provide an add-on which adds a button to the user's browser's toolbar and thus enables them to directly convert any web page (which they have currently accessed) to PDF.
  

Several other similar websites have already been covered up in the above response. So, I recommend you to also have a look at them and decide for yourself according to your needs.

As Prashant Dalal said,

pdfcrowd is the best website to convert your HTML files to PDF.
I have tried it and it works as we want.
Try it and check whether it satisfies you, then reply.

Another Site: document.online-convert.com/convert-to-pdf

These are the following ways to convert HTML to PDF
1.hgtm2pdf.com
Visit the site and convert the webpage to PDF by only entering the URL of that page. After entering the URL press convert button.
2.pdfmyurl.com
Enter the URL and press the covert options to get the PDF.
Some other sites are
Pdfaid.com
Pdfonline.com
Pdfonfly.com