Great quality of content

I am very happy with Target Test Prep, it has allowed me to improve from 640 on the first mock exam to 740 on real one.
What I like the most is the quality of content. The lessons are really well structured and though out until last details. Also each concept comes with a series of exercises, which allow to immediately practice. The quality of materials is much better than other courses I tried - as example, sometimes those would refer to some sentence as being "ackward", while TTP really explains what is wrong with the sentence.
Each lesson comes with a set of practice tests, and I really value they are split per level of difficulty. Flexible structure allows to really focus on what is important. Also the number of practice questions is huge.
As a remark, amount of content is too big to cover completely during preparation, unless you have 4+ months (2hr/d), so it is important to devise preparation strategy which works well individually for you and skip some lessons or topics, otherwise you risk being stressed out that you cannot complete it all in time.
Verbal part is being created as we speak so is missing some material, but the quality of content which is already there is excellent.
On negative side, sending feedback to the team seems pointless: I encountered a few questions which are misleading or have wrong answers (admittedly not many, max. 10 out of 2000+) and pointed out a few of them to the team, but they did not do anything about it, although from reply it looked like they would.