When your future and your career is on the line, you would choose nothing but the best. You would want to do your best for your college entrance exams or scholarship exams or other exams like the gmat prep. Opportunities comes only once and if you are not prepared enough, you might fail your exams and lose your chance to further your career or your studies.
I remember 20 years ago, I was a senior high school student and it was time to take a couple of exams for college. I didn't understand why I didn't pass the one I desperately wanted to get into. Maybe if I had taken review from Veritas prep, things would have turn out differently.
If you have the opportunity and the resources, don't take your future for granted. Instead, use your time and finances for the betterment of your future. Be prepared as many opportunities in life, come only once.