Lip augmentations usually look great and natural except when it comes to fat grafting. Lips injected with fat look huge since you have to over fill the lips a lot since most of the fat goes away in a short time and when it does go away, it gets lumpy bumpy.
Restylane or Juvederm ($550/syringe) looks good and is easy to inject so most patients get this first and later switch to the more permanent implants which now are soft and easy to put in ($1500-2000 per lip). Most doctors don't do fat injections anymore.
Web reference: http://www.TheBestLipoDoc.com