In the January 2006 Journal of Medical Library Association (free online), Rita Vine's electronic resource review, Google Scholar, briefly looks at the draw backs and other aspects of Google Scholar and other web engines.
In Vine's blog post, Google Scholar gets better at indexing PubMed content, but it's still several months behind, she notes that Google Scholar is improving but is still almost 5 months behind PubMed in retreiving medical literature.
However, Vine notes in her JMLA review that Google Scholar is a "worthwhile and useful search tool." Although Scholar has its problems, it can be an appropriate resource tool in medical libraries. "It is a perfectly decent search tool for those who are looking for quick answers and for questions where the outcome has little or no impact on clinical excellence. Google knows what libraries have been reluctant to admit: that users love search appliances that are fast, easy, and deliver the goods—or at least enough of them to satisfy their current information need. Plenty of information needs do not require powerhouse tools like MEDLINE."