Today I found two new reviews on the net:
Carsten Hansen's reviews at The Chess Cafe usually are very well written and thorough. Accordingly he often needs a little more time to deliver. Therefore I was somewhat surprised to see that The Ruy Lopez: A Guide for Black made it to the March edition of Checkpoint.
In general Hansen's review is very positive, but I am a little disappointed that he leaves out our main argument in favour of the Zaitsev: For lower and middle rated players, studying the Zaitsev mainline mainly should be considered a middlegame exercise. Seeing how modern top players handle such an exciting middlegame position and then trying to analyze it independently must be among the most useful things you can do for your chess understanding.
Although Phil Adams also seems a bit unconvinced about our choice of the Zaitsev as our main recommendation for Black, he too gives the book thumbs up. In particular I appreciate his conclusion: "A very good opening book. Readers will learn a lot about the Closed Lopez, and therefore about chess, even if they never play the Zaitsev! Highly recommended." This sums up our main message very well.
Addendum 8th March 2007
Yesterday I didn't seem to quite register Hansen's entire conclusion. Actually his "I highly recommend this book to players who are serious about their opening repertoires and about improving their overall game." is quite close to Adams' conclusion (and our main argument).