The edition of Rowlandson's book edited by Neal Salisbury is excellent. This edition contains Rowlandson's text, together with a wealth of other materials: a thorough introduction, many maps, a chronology, a bibliography, and other historic documents from Rowlandson's era. The many illustrations include photographs of the title pages of earlier editions.
Rowlandson's captivity narrative is a significant milestone in American literature; the introduction to the Salisbury edition notes that the text "has been almost continually in print since 1770." Since the text itself is relatively short, it has appeared in anthologies (see, for example, "The Harper Single Volume American Literature," third edition). But the many "extras" in the Salisbury edition definitely make it a book worth buying, even if you have an anthology already containing the Rowlandson text.
Rowlandson's memoir itself is not great literature stylistically. But it is a fascinating text with some really striking passages. Rowlandson's extreme evangelical Puritanism will likely alienate or bewilder some modern readers, but her religious attitude should be read in historic and cultural context. Similarly, her extremely racist descriptions of Indians ("merciless Heathen," "ravenous Beasts," etc.) should to be read in context (but should not be trivialized, especially in multiethnic classrooms where this text might be taught).
This book is a significant document of contact between cultures in times of extreme crisis. It is an especially intriguing text for those careful readers who really try to read "between the lines." Recommended as companion texts: William Apess' "A Son of the Forest and Other Writings" (Apess was a pioneer Native American writer) and James Fenimore Cooper's novel "The Last of the Mohicans."