Undergraduate Use of Federated Searching: A Survey of Preferences and Perceptions of Value-added Functionality should be subtitled "Count the number of times 'Google' is mentioned in this article" and has some good data for both those that like federated searching and that don't. The listed methods and rubrics are thorough, though they produced small statistical significance. To the visually inclined I challenge you to compare Figures 1&2, which are ratings of federated vs. non-federated search as given by undergraduates & predicted by librarians at a conference.
My "should be" sections are dedicated to Russ Hall. Should I start individually blogging each article?