a friend of mine used hbsguru and was pretty disappointed with the turn around time and lack of interest shown.
i just believe hbsguru is stretched thin.
i've used alex chu's help through gmatclub and he gave really good feedback.
i also used mba volunteers last year, and they were really good. i'd recommend them, considering it's just 100$ and the in depth feedback they offer, it should be an easy decision to try them out mbavolunteers.org.
Precision Essay's essay analysis in my opinion is out of the league. They really helped me in writing my wharton essays. They should be a solid bet to take advice from.
MBAgirl2010
If this is for Wharton - Alex C Fleming (an '09 grad and former adcom member) has also started doing consulting. He has a solid sample essay on his site and nicer pricing. PrecisionEssay is another option I know of - former HBS grads with excellent essay write-ups for the top schools and also more affordable. Either of these will probably give you more attention than the top two guys who do hundreds of essays per season.