Validity of Princeton Review Tests?

<p>I got a Princeton Review "Cracking the PSAT/NMSQT" book and was wondering how much accuracy they provide in how well one will actually do on the real test? To those of you who have taken them, how much higher/lower was it? Also, I was wondering if they have the same relative difficulty compared to the real test? Thanks in advance.</p>

<p>I think their math section was pretty good, slightly harder. Their CR section was slightly more difficult (I started prepping with PR and took 5 practice tests, and my first score was a 580 on a CB test, and on the first BB test after PR, I got a 680). The Writing is ok, except it has some errors here and there.</p>

<p>CR and Math are good, Writing is crap.</p>

<p>CR is good</p>