J.B.
I haven't heard of them and I am an SAT classroom instructor and private tutor. The company I work for is Revolution Prep and I definitely stand by our work. Princeton Review and Kaplan are also reputable companies.
A good company should be able to guarantee you a 200-300 point increase on SAT scores for students who complete a full course or tutoring package. My company charges $599 for group classes or for small group tutoring, which is live, on-line tutoring with no more than 5 students per tutor, which is similar to pricing from our competitors. On-line small group tutoring is like running a very small class in places where there aren't enough students to warrant a full live class. The on-line small group tutoring is our fastest growing segment and the students really love it. If you don't have a lot of test prep options in your area, you may want to look into on-line options. Most large companies have some reasonably priced on-line option that combines the liveliness of a group class with the attention and convenience of in-home tutoring.
Overall, I think that GOOD test prep is a good investment. One doesn't have to invest thousands of dollars to see results that will help with a student's admissions chances or merit-based financial aid.
ETA: If this is the company you're talking about, the lack of pricing on their website, the advice to rarely leave SAT questions blank (terrible advice!) and the poor grammar on their website would lead me to be very skeptical of their product and services. http://www.testprepseminars.org/classes.htm