They operate under the delusion everyone is trying to get a perfect GRE score. Programs in my area just use the GRE as a way to trim down applicants (so as long as you pass a certain level you're application isn't tossed) so I just needed some tips and encouragement. I find their approach really insulting- like if you don't get in the 90th percentiles you didn't do enough. Their book reviews are a joke. They said a certain book had the best quantitative prep but that was totally wrong. The book in question was much harder than the vast majority of GRE problems. Another book I found very helpful and very close to the real test they said was too easy. Avoid them unless you are trying to get into the 90th percentile in quant and verbal (but why would you want to?).