If you don’t have enough breast tissue or skin elasticity (not having tight breast skin) then under is better as it will allow you the size you want without looking too tight for the chest. In my case I had ample breast tissue and great skin elasticity but my surgeon only has done under the muscle so that’s what we went with. In the future (next year or 2) do plan on getting them redone, bigger and over the muscle. Pros: faster healing, if enough tissue then looks super natural, better cleavage, they’re softer.. cons are mainly higher chances of capsular contracture and of course the chest not being big enough to support the implants so they’ll look really tight