I liked it a lot. It is impossible to rate every poem in the book individually, but my overall impression is very positive.
The usual narrative of the WWI presents the war as aimless and melancholic affair that people just don't understand and don't want to participate in. This book shatters this narrative and presents many facets of this war: patriotic fervor of the beginning, hardships at home, disdain for pacifists and conscientous objectors, pro-war and anti-war discussion of the middle, and bitterness and unwillingness to forgive in the aftermath.
The book is very conveniently categorized by the time periods and different topics, with an introduction to each of these chapters. Finally, there are lots of poems by completely unknown authors (and of varying quality), so it is very refreshing to read. Oh, and there is even a list of such authors with a very short information about them - a quite useful thing.