Getting Confusing everyday; Google Scholar and Thomson ISI's Citation Index

A recent paper by Daniel Pauly and Konstantinos Stergiou compared Google Scholar and ISI in few selected disciplines. via UBC Google Scholar Blog Their conclusion is

"Thus, GS can substitute ISI, which so far has a monopoly(with the possible exception of Elsevier's very expensive search engine, Scopus)"

I did some of the same citation searches in Scopus and I got different results. Good luck to the scientists who are looking for tenure or promotion based on their papers citation.If I were a scientist or researcher trying to figure how many times and by whom I have been cited, I would have said (to use one of my customer's words) that this whole citations metric system sucks.