I first found out about Manhattan GMAT from a co-worker/friend of mine who had just gotten a full ride to Columbia Business School. She told me it was hands down the best course around, and that was all the proof I needed (the fact that she got a 730 helped too).

I actually took the course twice. the first time I was pretty swamped at work and didn't have time to keep up with the pretty demanding workload of the course (about 8-12 hours of work a week). Before I knew it 8 weeks had passed and the course was over. I didn't even bother to take any more practice tests because i knew I hadn't taken the course seriously. This course is great but you only get out of it, what you put in.

Fast forward a year later, and I hear that the GMAT is changing in June, so I take the plunge, sign up to take the course again and register to take the GMAT the last week in May (about a week after my final Manhattan GMAT class). This time around i buckled down, stopped going out on weekends, and kept up with the course curriculum. Needless to say, this dedication paid dividends! I ended up getting 10 points above my target score and got a 730 on the GMAT.

The course is great because of how thorough the materials are and how charismatic the teachers are. They take something that should be boring and mundane, and make it fairly enjoyable. The math section of their practice test is a little more difficult than the actual GMAT, and I think this is due to the difficulty level increasing much more quickly on the Manhattan GMAT exams then on the real GMAT. This could be considered a good thing though, because it forces you to really work on your time management, an essential skill for getting a good score on the GMAT.

Regardless, I definitely recommend Manhattan GMAT to anyone really looking to get a good score on the exam. Just remember that there are no tricks or shortcuts, the more you put into the course, the more you'll get out of it!