The first time I used PaperTrue, I was satisfied with the results. The second time they engaged two different people, one to do the first half and another the second. The two editors preferred two very different styles and made very different changes though all I wanted was proofreading. The first one added many errors to the paper and one also miscorrected terms used in my profession. It has been a nightmare to try to make the two halves consistent and remove the errors. Unfortunately, the version of track changes they use does not remove the editor's change if one does not accept it, so one must go back, correct and then remove the change. they offered to redo the paper but only if I waited a week. Their work is inconsistent, sometimes good and other times a nightmare.