What kind of dermabrasion has best results for acne scars?

Depends: It really depends on he size and distribution of the scars. Dermabrasion and chemical peels (possibly retinoid topical) can help with finer scars but for bigger scars may have to consider laser or deeper peels such as co2 peels - please see a cosmetics dermatologist/plastics surgeon.

Dermabrasion: Dermabrasion is certainly much better than microdermabrasion. However, treatment depends on type of scar, location and your skin type. Other options include fillers, surgical subcision, and lasers such as fraxel and fractionated co2 laser. Dermabrasion is done much less commonly than in the past because of these new tools. See an experienced dermatologist or plastic surgeon.