I bought the Economist GMAT Tutor Premium Prep 3 month plan on November 4th 2017. At that point, I had already been to some GMAT quant lessons in my city and knew absolutely NOTHING about the verbal part. On February 26th I sit my GMAT Exam for the very first time and scored a 720, Verbal 40, Quant 48.
I can honestly say that the Economist GMAT Tutor was the best preparation tool I could use. It's a very friendly program and it really taught me everything I needed to know in order to secure a good score. I was really impressed with the Verbal lessons, they carefully walk you through all the grammar you need for SC in a very interactive way. The RC and CR tips were also very effective.
The tutoring sessions helped me a lot, the tutors are really helpful and have plenty of experience with all kinds of students, so they know in which direction they need to point you.
All things considered, I think that the Economist GMAT Tutor is a damn good investment if you want a good score and I warmly suggest it to anyone planning to take the GMAT.