I have a different opinion.
If you expect someone to write your essay for you or prepare your application, than Admission Consultants are probably not going to solve your problem.
If, on the other hand you do not have someone who is candid, will critique your work honestly and will put in the hours necessary to read and re-read; or you are applying to schools where you cannot afford to make a mistake (because you are a stretch applicant), I think having an admission consultant help can definitely be worth the money.
At the end of the day, you can read through these forums day and night, but you will never know the business as well as a professional. Having someone who has been a member of the admissions committee in a leading school on your side will keep you "coloring inside the lines".
You are going to be spending a LOT of money on the MBA process. If you feel you need the support, I would check which one is most recommended and try him/her out for one school.