Almost essential if you aim for Q49+

I had the opportunity to use these tests to prepare for the GMAT for nearly 2 months. I decided to use them only once I reached at least a steady 47 in mock tests and 95%+ accuracy at 500lv questions and 85% at 600. At this point they are extremely useful in order to pinpoint new excellent and most importantly efficient strategies to solve some 600 and many 700 lv questions. It's also important to understand that these questions do not represent in an effective way the official questions. However, as mentioned before, they help you to think out of the box for the most challenging questions. I highly recommend this product to people who aim for at least Q49. Before the test I scored 49 and 50 using the official MOCKs and 49 many times using these Tests and I finally got 49 but very easily. In general do not rely to much on the score these tests provide but on the experience and strategies you can extract from them.