I am currently working on a committee that is reviewing federated search engines. We are looking into acquiring a federated search engine (or common user interface) for our library. We have a number of products on our radar. I’d like to know if anyone here uses a federated search service or similar product? If so, which product are you using and for how long, its advantages/disadvantages, and what the general consensus on the product is in your library: good, bad, indifferent? Any comments or observations are very welcome.