I regret not taking it in the first place!

To summarize my review: TTP is awesome!
I just had a couple of weeks to study using TTP because I had a due date on my second GMAT exam, but studying with TTP was an amazing experience, based on a few things:
1. It actually teaches you math.
I've seen other courses that teach you only a few tricks to get some questions right, but that is not sufficient to get a very high score. TTP has a methodology that ease the learning process to you, so those tricks are only ways to fasten the solving process of a problem that you'll definitely know how to solve if the trick is not enough.

2. It helps you to track your gaps.
After each exam you take, it clearly states what are your main problems, according to question type, theme, and difficulty level. It even conveniently lead you to themes that you should review before advancing on the study plan. After each test, you review your answers and the official solution, and you can mark why you got it wrong. It helps a lot to become more aware of the changes you need in you.

3. It has an "infinite" questions set.
Seriously, I wasn't even near finishing all the practice questions TTP could give me. In addition to questions grouped into themes, it even has a tool to generate customized tests with a lots of parameters for you to choose, such as difficulty, your average response time on related themes, only new/known questions, only questions that you got wrong before, etc.


4. It has an use experience that meets nowadays expectations
Seriously, why there are still courses that makes you use excel spreadsheets or things like that to track your progress? TTP gets that done easily! There's a pretty amazing dashboard that easily gives you the information you need to take the next steps.

5. The customer service is great!
I sent a few messages on the customer support chat and they answered me really fast, even on Sundays! Theses messages were all about my attempts to optimize my use of the tool because I was so short on time. I did not have any problem to use it.