Bought the book 12 weeks prior to the 2012 PSAT in October, my son has completed all the tests including the diagnostic test. It's really rather good test prep, he has consistently between 202 and 217, so I feel the tests are consistent and a fair reflection to the 'real' CB PSAT.
Compared to the Barron's 16th PSAT prep, it's better than the Barron's, which for some reason doesn't include a raw score/scaled score chart, so when adding your raw score, there is No comparison to the actual PSAT score rank, so you don't get a 20-80 score or each Critical Reading, Math, Writing section, which is just annoying and frankly stupid, for that reason alone, Kaplan is the better test prep book.
However, the Kaplan test prep questions are on average a little easier than Barron's, the writing extracts are shorter and easier to read than Barron's and the 'Real' PSAT so be aware, your score may not truely reflect your comparable CB PSAT score, but of the books available, I think Kaplan is the better one.
The book isn't organised that well and the answer sheet should be perforated to enable you to tear out and use separately, unfortunately if you are a little careless (like me) when you try to 'tear out', you'll wrip the answer sheet!.
Updated 12/2012 Student Scored a 209 based on this prep book, well worth the $10