It's pretty slick, but the I couldn't find a way to go full-screen? Something like 15-20% of the reading space is with headers and footers that serve no purpose while actually viewing documents.
Compare Google Docs native PDF reader to yours [Screen shots here: http://imgur.com/a/mfVJx]. If I'm using a service to view documents, I feel like more real estate for the actual content would be more useful than social sharing or download links or whatever else.
The viewer mostly based on PDF.js (http://mozilla.github.com/pdf.js/) with a customized UI. On server side, we leverage several components (incl. LibreOffice) to convert different document types to PDF.
Compare Google Docs native PDF reader to yours [Screen shots here: http://imgur.com/a/mfVJx]. If I'm using a service to view documents, I feel like more real estate for the actual content would be more useful than social sharing or download links or whatever else.