Best for Quant (PS &DS)

I definitely recommend giving this a try.

Pros:
The quality of questions is high.
More advanced 700+ PS questions
Advanced DS questions.
Verbal is above average.
The mix of genres in RC is excellent.
GMAT like UI.
Analysis of the test is excellent.

Cons :
The Scoring & Algorithm is not perfect.
Balancing of difficulties in Verbal and Quant is necessary.
No full-length test facility.
Some CR questions are not up to the standards.

Overall, It is good for beginners to improve their sectional scores.
Don't just go by their scoring, I guess that algorithm might not be efficient, Just evaluate your responses and compare across the previous test.