What's the difference between implant brands?

I could not speak to the implants mentioned other than Silimed because they are not available in the US.  As far as Allergan, Mentor and Silimed (sold as Sientra)  which are available: no practical difference. They are all FDA-approved, give good results and have similar statistics on durability. The implant manufacturers and their reps will try to focus on small differences they would like you to think are significant to get you to use their implants, but for the patient, they are all good, in my opinion

Only the Silimed implants of the 3 you mention are available in the United States,  they are imported to the US from Brazil by a company named Sientra.  I have used hundreds of the textured Silimed implants since they were made available by the FDA a couple years ago and have been extremely happy with their performance. I can not comment of the later 2 as they are not available in the US. 

Thank you for the question.
All three companies that provide FDA approved implants in the United States are reputable with good products (similar characteristics and warranties).  Every patient's anatomy and goals are different;  each patient may  benefit from the use of a specific size/profile of breast implant.  Therefore, in my practice, I have consignments of all 3 different breast implant manufacturers available in the operating room.   Ultimately, more important than the specific breast implant company utilized will be careful selection of your plastic surgeon. Careful preoperative communication, careful intraoperative sizing ( including the use of temporary sizers and dimensional planning/measurements)  and careful execution of the procedure will be key. I hope this, and the attached link, helps.  Best wishes.

I agree with Dr. Marcias,  as only Silimed (Sientra) is available in the US, it is difficult to comment on the other 2 you have listed.  I have been extremely satisfied with the Sientra implants for breast reconstruction and Mentor memory gels for cosmetic augmentation.  Hope this helps and best of luck! Dr. Chung