I do not know whether he is legit or not but I do agree with some of the statements on the website. His name has come up on GMAT Club before.
1) I agree that one-on-one training is often the most effective
2) I agree that a longer class period is generally more effective than a shorter one
3) I agree that the major commercial prep services often use a "one size fits all" training method that leaves much to be desired especially for students on the far right tail
On the other hand, there are some factually incorrect or misleading statements on the website. Data sufficiency is not unique to the GMAT, other tests have questions that tap the same constructs, and many tests have included questions that are essentially the same as Sentence Correction questions.
I did not find the CBA calculations on the website the least bit convincing, but others are welcome to disagree.