The principle of treating acne scar is the same as for any other scar. If one talks in terms of scar revision, it means you will get an improvement. However, one cannot get a flawless skin after the treatment. In acne scars, one can expect anything between 30% and 70% improvement after one procedure.
The choice of treatment will depend upon the types of scars and the extent of involvement of the face. Some scars can be treated by fillers. Most bad scars require resurfacing. This can be achieved by dermabrasion or by laser. There are different machines to achieve the same goal. There are subtle differences in the effect produced. For example, Erbium-YAG laser will cause little collateral damage with little heating of the underlying dermis. As a result, remodelling of collagen and hence filling of the depression fill be less. On the other hand, there is greater heating with carbon dioxide laser and hence better collagen remodelling. However, the operator has to be experienced, otherwise one can end with unwanted damage. All these are tools and the effect you get will depend upon how you use it. By merely using a latest machine one does not automatically get the best result.
Experiments are done and have to be done. Otherwise, there will be no advancement. Therefore, there are several variations with different names. Some procedures get established and others get discarded in due course of time. One way to decide is to check the results of the operator.