I used such a service and nuts, I forgot the name of it.
I can tell you though that I believe this may have been the service.
http://www.essayedge.com/
Seems to be what I used because the "Harvard educated" thing rings a bell.
Anyways, my personal statement though true and factual was very flat and boring. The professional editor rewrote my essay in a manner that was much more exciting but true to the original essence of my statement.
Actually it was a bit too exciting. One thing I considered is yes, these people may be English majors and may be better at us in writing but they don't know the audience that reads these---psychiatrists, some who have a self appointed belief that they can psychoanalyze personal statements. I was a bit concerned that the reader might think I was grandiose in a bad way.
So yes, it did help and it did dramatically improve my personal statement, but I got the rewritten statement, and basically just rewrote my statement on my own using some added zest and pizazz that the professional editor put in the new one.
All in all it did help. The editor was able to show me how to soup up my statement to make it much more colorful, but its not like they should write it for you. Besides to some degree I would find that a bit unethical.
Again, I don't know if it was the same service, but the service I used did keep in contact with me and ask me on what I thought on their essay editing advice. I would reccomend such a service.