Worth the money!

I only used TTP for their quant program. TTP helped me go from a raw score of a 37 to a 49 in 3 weeks. My advice would be to go through the Manhattan GMAT prep books first, then tackle the Official GMAT questions to figure out your weak points. Once you have done this, you should go through the TTP Quant program to really hone in on your weak areas. Of course, while you are doing all this you should also be studying for Verbal and taking a practice exam every weekend. I think what makes TTP so great for Quant, is the rigorousness of the program itself. You end up answering a crazy amount of questions by the end of the program, but I think this is key to really ensuring you will be able to answer the question come test day. I would 100% recommend TTP.