Hi, I am preparing for Veritas Prep. I have prepared from their free DS PDF book and it was really good. I have enrolled for their test series during a sale event from them. I am not at all disappointed with their tests. They are very good with excellent quality of questions along with test analysis.
I suggest everyone to definetly try Veritas Test Series as they give lot of insights into your prep. The tests can be little more difficult than the actual exam but thats the whole point of attempting mock tests to prepare for the hardest scenario in the actual exam.