Silicone dressings and topical treatment can be beneficial in the treatment of scars. Several studies have illustrated that treatment of scars with silicone gel dressings clinically improves scars, especially in patients at high risk for problematic scarring. Silicone dressings are believed to decrease scar via wound hydration, increased static charge (i.e., silicone gels contain increased negative static charge), and modulation of growth factors. Scar hydration with Aquaphore can help as well. Applying Aquaphore twice daily to scars along with massage can help improve the look and contour of scars. Mederma, a topical onion extract, can decrease the appearance of scars when applied with scar massage. The key to most scar treatments is scar massage.
To know this, someone would have had to have done a head to head comparison as a study, and no one has. Both products are silicone gel based, and chances are they are close to identical in outcome. Best wishes.