I began studying for the GMAT with materials from Manhattan, McGraw Hill, Magoosh, and the Official Guide questions. On my first crack at the real exam, I did not meet my target score. I was considering other very expensive options like the MGMAT in-person course or private tutoring, but a friend recommended Target Test Prep and it ended up being the perfect course for me.
The course overall is very well-designed, both in terms of the actual curriculum and also the UX. It leads you through very methodical coverage and practice of the material, building on the concepts so that you retain all of the earlier chapters. I also really liked the Analytics features that made it easy to keep track of the average amount of time I was spending on each problem, and what kinds of problems I got wrong most often. I really wish I had heard of Target Test Prep before I bothered with other materials because I probably could have gotten sufficient preparation with just this course and the Official Guide - and it's offered at a very reasonable price too. I even found a promo code online so it was definitely a great value!
True to its name, I was able to hit my target score on the actual exam after going through this course. I wouldn't hesitate to recommend it to anyone looking for a flexible online prep option.