This is review for Quant section only. I took the GMAT for the first and final time two saturdays ago. I just received my official score report and I'm satisfied with the overall result.
Big thanks to Math Revolution for my quant score. I purchased the all in package plus the Special Questions Pack and the 700+ level questions pack. If you solve every single questions on this website, which by the way is no easy feat, I really believe you will be fine on the Quant section.
One thing MathRevolution gets right, compared to Manhattan or OG, is the actual level of question on the exam. I truly felt the questions on the actual exam were much similar in difficulty levels to the questions offered by MR. I did the Manhattan CAT, but these questions really were way wordier than the actual exam.
I solved through the quant section pretty smoothly... until I got stuck on a set problem. I told myself I'd skip a question if I couldn't solve it under 5 minutes. 6 minutes later, I couldn't let it go. I ended up solving it but ran out of time on the last two questions and pretty much had to guess. Maybe I would've scored 51 if it wasn't for my ego... Anyways, I really recommend MathRevolution for Quant.