Not that you asked, but I'm not sure of the value of these services for residency applications.
For one, their self-professed expertise is in writing personal statements for SCHOOL. Residency is not school and the PS are generally written in a different light.
Secondly, since PS tend to be less important than for medical school, I'm not sure you couldn't come up with a decent one on your own. The vast majority of residency PS I've seen are middle of the road, boring. A few are so perfunctory as to beg the question, "why'd you even bother?". And a few are fascinating, interesting reading. If an essay service can help you get into the last category, that would be worthwhile - of course, just like all things in life, you have to get to the point where people actually read your PS. If your scores and grades are low, at many programs that won't occur.
Still, I encourage people to try and spend some time on their PS, if only because I know several programs commented positively on mine and I'm sure it helped me get at least one or two interviews.