Zotero is also able to pull full-text directly from library databases (like EBSCO) whereas with Mendeley you need to save the PDF to your desktop and drag it in.It also saves a snapshot of the page, which Mendeley does not do. Zotero does a better job than Mendeley of pulling in website data.For all other browsers, there is a bookmarklet that you can add.
Mendeley or Zotero, which one is right for you? These two tools are very similar, and, for the most part, they function in the same way.