Again, I think a consultant helps you market yourself (your child) better. The problem with being a "star" at Exeter (I would guess; I went to my public school in KS, LOL) is that there are lots of stars in your class. Harvard, Yale, etc. will only take so many Exeter students, etc.
A consultant could help your child find the unique things that will push their application to the top of the heap. You could do that too, if you know how to market them, etc. I don't agree with this, BTW.
Alot of non-Chinese people pay for consultants too. We live in an area where there are ALOT of "Tiger moms" and Asian overachievers. (I'm generalizing; my doctor friend, who is from Taiwan, told me her kids "failed out" of Chinese school b/c she was such a lousy Tiger mom!). Some of them get dinged with their college applications for getting perfect SATs, perfect grades, playing piano, etc. Being a stereotype. I could imagine such parents hiring a consultant to make THEIR kid look different from the OTHER kids who have very similar credentials.
When I got into Harvard Medical School, my boyfriend at the time (who was at Harvard Law) said the only way to get into Harvard was to teach underwater basketweaving to Burmese peasants! You get the general idea.