When it comes to beauty treatments, it is not just a matter of operating a machine or administering a certain technique.
There is also the matter of art, which brings into the equation variation in skill, taste and judgement. Practitioners are neither equal nor the same, the same way painters produce widely different works of varied calibre, even if the tools they use are largely the same. Be careful to research, and speak to the practitioners to find out as much as you can before committing to anything. Assurance and agreement of the desired effect of any procedure requires meaningful communication between doctor and patient.