640 to a 740! Here's my journey:

I started with a 3-month class-style course with Manhattan prep. It was an online course with 4 hours of class per week. This was great as I managed to cover all the required topics and brush up on my skills. After completing this course I did the GMAT and scored a 640 (Q52, V76). I definitely wasn't happy with this score and knew I could do better!
MPrep offered a free post course assessment (PCA) (which I did prior to the test) and then they also offered a free post exam assessment (PEA). This PEA helped me tremendously by pointing out specific areas I should focus on to bring my score up to a 700. I went on to take 3 hours of private tutoring with the same instructor who did the PEA. I then did the test again 5 months after the first test and this time my score went up by 100 points to a 740!

The PEA and private tutoring were gold! I would seriously recommend them in order to be able to put all your energy and effort towards specific topics which can actually help bring your score up instead of wasting time on trying to get the 'high-hanging fruit'.

My 3-month course instructors were Eric Garthoffner and Pedro Ledesma who were very thorough and kept me committed to a regular study schedule. My PEA and pvt tutoring instructor was Chris Gentry - he was phenomenal and continued to stay in touch much after my sessions ended and right up till the day I gave the second test with constant motivation and prep tips.

I would highly recommend Manhattan Prep as a resource to prepare for one's GMAT.

Good Luck!

-Komal
740 (Q77, V96)