The round cosmetic breast implants are symmetric, so their orientation and location is never problematic. Round is more commonly used than anatomic, because they tend to look more natural in both the upright and lying positions. Round implants are less expensive, as well.
Anatomic: Anatomic or tear dropped implants are asymmetric. The bottom of the implant has greater outward projection than the top. Shaped implants are very good at providing shape when there is little natural breast tissue. Shaped implants have the potential to rotate, though, which can cause serious problems. Your surgeon must make sure they are properly oriented or they will project farther in the wrong place. Dr. Vitenas recommends the round implants, as they reliably provide a more natural and organic look.
Smooth: Smooth breast implants are most commonly used, as they move very well in the breast pocket. Smooth implants have a thinner outer shell (versus the thicker, textured shell), and therefore feel more natural and soft. They are less likely to ripple, and smooth implants generally cost less than textured implants.
Textured: These were designed using the school of thought that texturing implants would lead to a softer result, with less capsular contracture. This does not always happen in real life trials, though. Textured implants can adhere to the surrounding tissues, and do not move around as naturally as the smooth implants. The texture can lead to more rippling, as well. Dr. Vitenas recommends smooth breast implants, due to their natural appearance and soft feel.