Disclosure: I am taking these prep classes and practice tests to help my son prep for his GMAT test. He will start prepping in Jan’18, and will apply for Fall ’19 via the Consortium. I’ll be his study buddy. Also, I want to know what my money will buy. My bonafides: UT AUSTIN MBA’90, GPA 3.41, GMAT 630. (I don’t test very well.) Decent career in small business consulting. Been there / Done that. Anyway...
So far, I have taken advantage of free GMAT prep classes from 5 different vendors. During my brief encounter with their services, I believe their star ratings are correct. What I object to are the constant innuendos (during on-line classes), adverts, and emails that stress reaching the holy grail at the “700+ level.” (DS problem: After spending 3 months and $1,500+, I will achieve a score >700. Given: 1) average of 556, 2) standard deviation of 120...AD / BCE?)
Unwelcome comments include remarks such as, “MBA schools don’t want students who can’t do X.” Vendors then proceed to suggest (push) more (and expensive) add-on services. A situation exists (in the GMAT world / prep industry) akin to either an arms race or an addiction. The providers ensure their profits by fanning the flames of insecurity (and fear) among their captive audience. This is shameful. I think this scenario also violates anti-trust statutes. This is a cartel.
Another issue is the overfocus on your GMAT score. Once accepted into an MBA program, your score is meaningless. The score will not affect your grades. No one will ask about it and you will face “regular” math problems. At any top 50 MBA school, you will also enjoy plenty of math, language and writing support. Focus on the rest of the application process. If you scored 680, leave well-enough alone and enjoy the ride. Hook’Em Horns!