I have used Veritas books and online tests as well as mobile app. It's materials are most logical and it feels as if they know what you are thinking and have crafted the material accordingly.

The system is good, works as you would expect.
Positives:
- Unlike MGM, Veritas has moderate level Math questions, this actually helps you retain the level of confidence that you ll end up having in the actual test.
- The question bank is broader than other test platforms. This means that your scores don't get affected by non-availability of questions in the question bank, leading to you scoring extravagantly high.

Negatives:
the test interface is not the best in class. The answer descriptions are small and ambiguous at times. Having said these things, I believe they are not a deal breaker.