My friend Colleen Harris called my attention to a new bibliographic manager program called Mendeley. I spent a little time trying it out today. I want to stress that this was a brief test run, and these are, as the title of the post says, just first impressions.
Mendeley, presently in version 0.6 beta, is free (but not open source), and runs on Windows, MacOS or Linux. I tried out the Windows version. It's got two components: a separate desktop application like EndNote, and web-based storage for references. Add a bookmarklet to your browser toolbar and you get a somewhat Zotero-like experience of saving references from many databases and other sources like Amazon and Google Scholar. (It didn't work with my library's catalog, but did work with Worldcat.org.) You can save either single citations or pick from a list of search results.
It took me a moment to realize that citations were being saved to my online Mendeley library, and wouldn't appear in the desktop application until I pressed the Sync Library button. This is a different experience than I'm used to, but wasn't much of a hassle. The desktop client looks a lot like the Zotero interface (but outside of the browser window, obviously), and if you're used to either EndNote or Zotero it will seem familiar and easy to use. If you're using Mendeley on multiple computers it should be easy to keep your libraries in sync, a feature that Zotero 2.0 has but EndNote lacks entirely.
There's also a Word plugin that installs as part of the setup. It didn't work for me at first, and gave me an error message requiring me to reboot before it would work. The instructions in the error message were full of horrible spelling mistakes, which is a superficial complaint but didn't really inspire me with confidence. Once I rebooted, it worked fine, and the process of inserting citations and creating bibliographies is just about identical to Zotero and EndNote.
Mendeley is clearly geared toward academics: there's an online profile associated with your web account that includes publications, grants, and classes. It fills in suggestions for the name of your institution as you fill out your profile, and I had a hard time forcing it to accept "Georgia State University" instead of "University of Georgia - Georgia State University" (we're a separate institution, not a unit of UGA, as Mendeley seems to think all of our state institutions are). There's a My Publications group in the desktop client, and you can add publication credits to your Mendeley CV by dragging references here.
My first impression of Mendeley is that it's easier to use than EndNote, and probably not quite as easy as Zotero. It's not quite as mature as either product, but casual users and students probably wouldn't notice many lacking features. The missing ability to import citations from library catalogs may bother a lot of potential users, but searching Worldcat or Amazon is a pretty easy workaround. The online storage puts it one up on EndNote, as it's a lot easier to use than EndNote Web, and users who prefer EndNote to Zotero might want to consider Mendley as a free replacement. I'll be keeping an eye on it.