Amazing resources and great knowledge (David Mahler FTW)

Manhattan GMAT's course was really really helpful. In addition to well thought out curriculum that helps you go through all the 10+ books efficiently, they have tons of resources available online. There are labs (video guides on specific topics), interactive integrated reasoning materials and practice software.

OG Acher is another great resource, it let's you practice questions, records the time spent and generates reports so you can track your progress. It also has video explanations for many of the official guide questions.

Now, on the instructor, Dave is really amazing, you can tell he knows how the test works. He is able to keep the 3 hours interesting, stress important points and explain concepts efficiently!