I am familiar with the First Search option for searching our catalog, and I like it for several reasons:
1. It has a more intuitive (or at least more familiar) interface compared to the "regular" WorldCat or ALEPH.
2. If you use citations software (such as EndNote), you an export a full citations (ALEPH can't), and First Search provides a more complete citation compared to "regular" WorldCat.
I searched for the title "Unfamiliar Fishes," a book about the annexation of Hawaii I read recently. There are 1343 libraries worldwide that have the print version of this edition, the first one listed is Augustana College in SD (interestingly, I checked it out of the Univ. of South Dakota library, and we are not listed. That may be because this book is part of our "Best Sellers" collection, which are mostly "rented" books - our library doesn't own them; but it should still come up in the catalog). The call number in LC is DU625.
When I clicked on the author's name (Sarah Vowell), I could see that she has written several other books (and the results list shows multiple versions of each title, such as audiobook and large print).
When I tried the OAIster database (I always forget about OAIster!), and put "South Dakota" in a subject search, the first result that came up was "Flood Tracking Chart for North Dakota" ; -) (I assume the document contains something about South Dakota), and the title I chose to click on was: Gastrointestinal Morphology of Female White-Tailed and Mule Deer: Effects of Fire, Reproduction, and Feeding Type, because who isn't interested in the gastrointestinal morphology of female deer?
Overall, I like the First Search WorldCat interface. It seems to "work better" than ALEPH, and there are more options, such as OAIster.