Dartmouth, one of the first two (I think) libraries to sign on as beta partners with Serials Solutions' Summon Unified Discovery Service, has opened the beta up to its entire campus community. And you can search it too! You'll find a prominent link on their home page, or you can jump directly to the search page. A brief overview of the product for their users is also available.
So whattya think? About the speed, relevancy, accuracy, or in general? The University of Calgary is also a beta partner with this product; we've recently had our MARC records loaded, and are awaiting the inclusion of metadata from some of our other local collections before opening it more widely to our clientele.