Microdermabrasion, as the name implies, is any procedure that very superficially mechanically abrades the skin. Aluminum oxide crystals, synthetic diamond particles, brushes of all kinds, etc. have been used for this purpose for a number of years. The effect is not much different than if you vigorously used Buf-Pufs, Loofah sponges, Clarisonic brushes, or even a vigorous scrub with a wash cloth or gauze pad. For this reason, I find them best for refreshing the skin and giving it a glow. I would not rely on it for treating acne scars, which run deeper in the skin.
For individuals with mild sun damage, skin roughness, slightly irregular pigmentation and very fine wrinkles, the results of a series of microdermabrasion treatments are typically somewhat smoother skin, improved luster discolorations, and perhaps subtle diminution in the appearance of fine wrinkles. I have no objections to microdermabrasion for anyone seeking a pampering, spa-like treatment experience.
In that same vein, a series of fractionated laser treatments are perhaps slightly more effective in this regard than microdermabrasion. However, here too, in my experience, the results are far from dramatic and often disappointing to patients expecting more from their treatments and economic outlay. (Ablative carbon dioxide laser treatments, on the other hand, are aggressive and can rival true surgery with potential series consequences and prolonged downtime and healing times; these should not be confused with the milder fractionated laser treatments and are best employed when serious skin resurfacing is required).
For persons with more pronounced wrinkling, scars of all kinds (including acne scars) and discolorations, there are many more appropriate, effective, and more cost-effective treatments that are available. Depending upon the individual circumstances, these range from chemical peels of all kinds, manual dermasanding, radiowave dessication, subcision and medical microneedling, to name just a few.
Of course, consultation with a board certified aesthetic physician who is skilled and experienced in all these modalities and who can create a treatment plan for all skin problems present is the best way to ensure that all your needs will be addressed properly and most cost effectively.