I've had good experience with this as a patient and practitioner (I am an RN at a medspa in LA). Best results seen when done in a series of three one month apart. The technique of the person administering the treatment is important.
Keep in mind it is not surgery. If you have a lot of laxity and are looking for a surgical result, might be better to go that route. Great for people just starting to notice some sagging who want a natural looking lift without going under the knife.