This is one of the friendliest forum, and the most useful one that I know. The members are very helpful, and I feel that we are trying to ride the wave together.
Please allow me to share my experience and opinion. I aced the GMAT quant in my first attempt, just by reading the math review in
the official guide, studying and taking the tests in the
OG for a week. English is not my mother tongue so I was not that great in verbal, and we were not aware of the availability of test prep books back home. These got me into Cambridge University. My professor didn't encourage me to think too much about scores. The role my GMAT score played in my admission was probably only to ensure them that the high marks in math I got from my college was not because my programme was too easy. I don't think they would judge my application differently if I had been classified into the 97 percentile instead.
To be honest, I am pretty sceptical about GMAT (and SAT, GRE, etc), at least given their current design. I wonder if the Kaplan founder (along with others who also scored 800) could sit the test n times and ace it n times also. I wonder if they can answer the questions correctly if the multiple choice format is abandoned.
Someone with a score of 800 isn't necessarily smarter than someone who scored 750. Those 800 scorers might not be able to solve some complex mathematical problems encountered in the real world, or some problems that take serious innovation and modeling ability. Same with verbal. The GMAT measured test taking skills, and the extent to which it can accurately predict academic performance still needs a lot of improvements. Yes, the correlation could be positive, but how big is the positive value and is the sample representative? The problems are too easy, for GMAT and GRE quant, they are even easier than high-school math. Plus, there is too much opportunity for guess work.
Kaplan book teaches a lot about number plugging, etc. That's definitely test taking skills, and can skew the test results as people who cannot develop simple models for some questions can easily guess. You are not going to find that in real life. However, we had better judge our abilities not just based on the score, as we'll end up putting ourselves into trouble if we enrolled into schools that have academic challenges more rigorous than our brain can naturally handle. Okay, on the one hand I will be as worried about my GMAT score when I am applying to schools, we are all on the same boat. On the other hand, I wish that GMAT (and SAT, GRE, etc) will be improved so that high score is only awarded to those who really deserve it. Just eliminate the chance for guessing and make the test more fair. Let's see if Kaplan can survive its claim when the test format changes. i.e. I heard that SAT's quant was recently adjusted to get people to enter the answer digitally. In other words, it is not multiple choice anymore.