Above the pectoralis muscle implants (Subglandular):

Ease of removal:
When the implant was placed above the muscle the capsule will stick to the undersurface of the breast tissue and the top of the pectoralis muscle (the fascial layer). Generally, it is easier to remove these implants en bloc because there is less concern for going too deep as the muscle is protecting the rib surface. The surgery will usually be quicker as well.

Cosmetic Appearance after removal:
Since the implant is sitting above the muscle it is directly stretching the breast tissue and skin. This can lead to more cosmetic deformities such as folds or creases in the breast after removal if the patient doesn’t have a lot of natural breast volume.

Recovery:
Post-operative pain is less for patients whose implants are above the muscle. This is because the capsule is not adhered to the rib surface. Surgical drains will typically put out less fluid and be able to be removed quicker for subglandular implants as well.

Below the pectoralis muscle implants (Subpectoral):

Ease of removal:
Subpectoral implants will stick to the undersurface of the muscle and the top of the rib surface. This makes removal more tedious and time consuming.

Cosmetic Appearance after removal:
Since the pectoralis muscle has kept the implant against the chest wall there has been less stretching of the breast itself. Therefore, some of the elasticity in the breast skin has been maintained.

Recovery:
Because the capsule needs to be removed from the rib surface and off the undersurface of the pectoralis muscle pain can be more for explant patients with a subpectoral implant. The drains generally put out more fluid for a longer period of time as well.