This is exactly the book I needed for my Tristan-Isolde project. Ferrante compares five major redactions of the Tristan legend, four poetic (Béroul, briefly; Eilhart; Thomas; Gottfried) and one prose (the Tavola Ritonda), examining the episodes they cover (or omit) as well as commenting on overall structure and major themes. I dearly wish she had included Malory among the others, but I understand how this would have been beyond the scope of the project.
While Ferrante’s preference for some redactions over others are clear, the comparison nevertheless brought out many aspects of the legend I had never considered, and gave me new avenues down which to direct my project.