What is your background? If you're highly quantitative then the Official guide is sufficient in terms of the types of questions you're likely to see on the actual test.

I scored over 80% in Quant and didn't feel that the questions in OG were very easy. Although, a lot of other people who have taken the test feel that way. So, the opinion is mixed. If you have a very strong mathematical/analytical background you should also try some sample questions from the ManhattanGMAT question banks, challenge etc. Some of the questions there are much more difficult than anything you see on the actual test but, they have good explanations and really break down the strategies which may be useful.

Thank you both for your input.

I would say that my math is relatively good. I graduated with a Finance degree, and have passed the CFA Level 1 examination. I also work in Capital Markets.

However, with all that said, the math that is tested on the GMAT is completely different. I use a calculator and excel files everyday, so trying to do numbers again in my head is just hard to get use to. Plus, I never use roots or exponents on a day-to-day basis. I've started to document questions and focus more on technique and where I went wrong in certain questions. I'm finding that helps a lot. If I do have time to go through the Manhattan questions, I will definitely give those a try, I'm just under a time cruch (writing the end of January! YIKES!)

Thanks again for all the advice.