The Economist GMAT is the best material to beat the quant section of the GMAT. I am an engineer with a strong mathematics background. However my mathematics knowledge is completely different from the one that is needed for the GMAT quant. In fact I've learned how to do calculus steps by steps and prove difficult mathematics theories, but not how to guess , nor to do basic computations in the most effective way and solve problems in 2 mins. Therefore my results on the quant on the very first simulation tests were frustrating. I then decided to take a course to improve my score. I tried the Economist GMAT tutor for 7 days (there is a week free trial ) and noticed at the very first day that it is the application that I needed. The availability of the apps on Android and Windows devices is very useful. I was able to practice in the train while going to work every day...

The course is computer adapative. You will have the questions on the same topic until you ace it. You cannot move to another chapter if you don't do reasonnably well on the previous. The one to one tutor session via skype is really valuable. I was abe to talk to my tutors who gave me precious advice to strenghen my weaknesses , to manage efficiently the time. They even go through my simulation tests and tell me how to do improve my score.

It proposes a really time saving template to write essays.

I found the verbal courses good too but less effective as I am not a native.

I highly recommend the Economist GMAT to learn the technics to solve the quant problems and the essay.