Unders have a longer recovery process as they are touching your chest muscles, because you have muscle and breast tissue covering the implant, unders can be more beneficial for those who have very little breast tissue to start with as there is more to cover the implant. With overs the recovery time is shorter, and your new boobs will move and feel more like normal boobs because they’re not held in place by your chest wall, from what I’ve seen unders can make the implants sit higher on your chest and my friends literally don’t move, they’re held in place. I had the choice and I’ve gone with overs, as this is what my surgeon recommended and I’m a 32 A 🙂