I have been given the task of exploring possibilities were our library to decide to move to more online reference works. Oxford offers a number of reference books online, but when we looked at the titles, none of the librarians was particularly interested. I asked for a quote from Cambridge Histories and it was outrageously expensive, even after the PALINET discount. Today we got a CHOICE card that covers Credo Reference, which seems worth looking into.
I'm a more than a little boggled by all of the issues involved. The first is can we afford it at our little school? Most vendors consider a "small school" to be 5,000 FTE, and even a school that size has a much bigger budget than us at about 1,300. Some reference resources are a one-time fee with annual maintenance fees, and some are flat-out annual fees like a regular database. Some allow you to select individual titles, some are whole collections. How any of them work with Reference Universe will be important to us deciding whether or not to get them at all.
I really love reference books and am always so happy when I take the time to look at them. I think all libraries are watching students skip the reference step and go straight for Web sites, books, and articles. Some libraries report more use of electronic reference resources, and if students are more likely to use those, then they are definitely worth pursuing.