Quality questions and good discussions

I found quant questions very conceptual yet very challenging. It provides good exercise for Quant and also prepare for GMAT test well in terms of thinking. The most fascinating part after the quality is the discussion link; and mostly I found that I had quite similar questions and doubts which has already for discussed in the thread and by reading the discussion for 80% time, my doubt gets resolved.

Also I like the environment of the test. Specially the flexibility to take topic wise quiz;
Also I liked the feature ,in which I can select few questions from review and recreate a mini test out of it; for instance, I can group all the incorrect questions and attempt them again. Also I found the Graphics, very informative and motivating.