Im Against Synthetic Injections for Large Augmentations

Bio-alcamid and other fillers are probably  a good option for the face, where the filler can be used on small areas.  We are talking about using 2-5cc here.  For the average buttock augmentation, though, the volumes are in the hundreds of cc's. 

You cannot inject that amount of filler and expect a finely contoured result that is free of lumps or bumps.  I also see questions on these very boards asking what can be done to remove permanent fillers.  What happens as your tissue naturally moves wth the aging process ?

In the face at least, I don't think these permanent fillers move with the tissues in a natural manner.

Your own fat is a much better option, and implants a distant second.