With Google Books you can search the full text of the books it has scanned.
The books come primarily from two sources: publishers and libraries, including those at Harvard, Oxford, the New York Public Library, the University of California, the University of Michigan, and Stanford.
You can download PDF files of entire books if they are out of copyright (usually that means published before 1923) or if the publisher has opted to allow it. You can specify that you only want results with full text.
You cannot sort or filter your results, and Google Books lacks many of the features found in Scholar, such as citation export.
Clicking the titles in your results list reveals useful options, such as Find in a Library.
Try a search or two of your own, using both the All Books option and the Full View Only option. If nothing comes to mind, search Hamlet both ways.
The new way that BobCat presents results will display the full text of an electronic edition, including a "Google Book," if it is available. To see this, search BobCat for the words "book of tea Dodd" (quotation marks not necessary). When you click the GetIt link on the results, you will have a a couple of electronic versions from which to choose. The one that says Internet Archive will take you to the Google "edition."
The scanning is quick and dirty; this affects search results.
Use the Advanced Search option with care; Google's indexing is not always reliable.
The scope of the project is unclear.
Copying, pasting, and printing are difficult at best.