I had it done 3 years ago at the Department of Oral and Maxillofacial Surgery at a university hospital. The issue was facial asymmetry.
To start with the conclusion, I’m not completely satisfied. The bones became symmetrical, but my lips and skin didn’t fully follow the movement of the bones. Still, it is better than before. Unless I make exaggerated facial expressions and take a front-facing photo, the asymmetry isn’t very noticeable.
For those who want to get double-jaw surgery for the same reason as me, don’t expect an extremely ideal change. Looking at other reviews, they all seem to say similar things.