I've been going through this book slowly, savoring each of the page sized reproductions of Schwitters' work.
I recently saw the Menil collection show at Princeton -- the reproductions here (almost) capture the power of seeing the work in person. The printing quality is also exquisite: the pages are thick, with a full range of the colors and a level of detail that allows you to appreciate all of the subtleties of Schwitters' work.
I can't really comment on the essays accompanying the text. At first glance they are interesting and informative, but I've been too distracted looking at the pictures to give them the attention they are due.