Yeah, mine for example.
When I viewed the demo on page you linked to, my browser tried to download the PDF, as opposed to display it.
It was also accompanied by a warning that this type of file can harm my computer.
In my case, I understand what is happening so can react accordingly, but I could imagine this scaring away a percentage of the users who think you're trying to fire malware at them.
If one could combine pdf.js (see link above) which bills itself as "an HTML5 technology experiment that explores building a faithful and efficient Portable Document Format (PDF) renderer without native code assistance" with this technique, I think you'd really be on to something.