My unlucky experience with essay mills has taught me that you should never pay someone to write things that are really important for your career or GPA. Writers do not care about your life and they never put as much effort as you would into serious letters, essays, or applications. This is why you should do important stuff yourself. I find this service useful for smaller things like optional papers professors offer for additional points. It's not that I ever had problems with the papers from this service, but I'd rather not make my life harder by receiving an awful paper and wasting my time on trying to fix it.