Amazing number and variety of questions

I found the questions very challenging yet satisfying. The verbal exams definitely have something weird going on with the scores but if you ignore the score and concentrate on the material, you can see improvements. Also gives you the confidence that if you do well here, you are pretty much set.
Quant like many say is the star here. The number of tests really makes you not worry about running out of questions, so you can really practice your timing or accuracy depending on your preference. You will also get a disproportional amount of 700 level questions, but they will be stacked together which simulates the GMAT as well as possible. Again if you are scoring high here, you can be confident that when you try the official GMAT, you will be finding it much easier.
Overall I have had a really positive experience. The scoring algorithm good dent your confidence a bit, but know that its good in the long run.