Free, open source, easy to learn. * Available as Firefox browser or standalone. * Good for capturing citation information from web documents. * Can store PDFs. * Allows user to highlight text and take notes. * Allows users to tag records. * Offers MSWord Plugin. (Zotero Quick Start Guide)
Costs money. * Relatively complex to learn. * Includes sophisticated tools for organizing and citing references, and creating bibliographies. * Highly customizable. * Can handle large numbers of references.
Costs money. * Accessible from anywhere via the web. * Good for managing records for articles and books. * Allows users to share citations. * Users may download optional add-ons: Write 'n Cite (an MSWord plug-in) for automatically creating footnotes and reference lists; RefGrab-It for capturing web pages.