One of VuFind's main goals is to be a user-friendly, intuitive search system. This page is designed to provide more detailed information on VuFind's usability (and how to test it, should you care to).
Doing Usability Against the Catholic Portal - This blog post describes procedures for usability testing used by CRRA against their VuFind instance, the Catholic Portal. It also includes some findings from the first round of testing.
Usability of the VuFind Next-Generation Online Catalog - Online comments page for an article from Information Technology and Libraries discussing VuFind at the University of Illinois at Urbana-Champaign (free full text not available).