I took the GMAT twice using Magoosh to prepare. Each time I scored a 700. I knew I could do better, but was reluctant to shell out the money for a class. I finally took the plunge and signed up for a Veritas class with Ravi, based largely on the stellar reviews here.

He is an incredible instructor. You can tell he knows his stuff and actually wants his students to improve. He provides you with many useful frameworks and, most memorably, sound bites/quotes which stick in your head on test day. After the course, I retook the GMAT and scored a 740, a 40 point improvement.

If you attend classes with Ravi and do the work, your GMAT will improve. It's as simple as that.