Zotero is the only research tool that automatically senses content, allowing you to add it to your personal library with a single click. Whether you're searching for a preprint on arXiv.org, a journal article from JSTOR, a news story from the New York Times, or a book from your university library catalog, Zotero has you covered with support for thousands of sites.
Zotero collects all your research in a single, searchable interface. You can add PDFs, images, audio and video files, snapshots of web pages, and really anything else. Zotero automatically indexes the full-text content of your library, enabling you to find exactly what you're looking for with just a few keystrokes.
Complete integration to web databases and to several word processors including word and libreoffice. Easy hassle-free inter-plattform (linux-mac-PC) single document editing facilities. easy- intuitive interface and the reference database can store several thousands of cites. It is Freeeeee, download it so support improves
Inserting the references could be easier, because the menu is hidden in the last tab of the las tab in the main menu. But that is more an issue of the word processor than of the zotero.
Try it, won't have a problem learning it, use it and forget about end note or reference manager.