When I was there at Yeson, there were other patients who were there for other stuff, as in male patients who were obviously not there for feminization. Dr Kim also does a fair amount of medical charity work with kids.
I think he is definitely doing something different. The "AAC" portion of VFS-AAC is probably what makes the difference in his procedure. In an old CNN interview it was mentioned that he developed this procedure to treat cis women who had androphonia as a side effect of anemia (which I also suffer from).
Either way, yes, it is a personal choice. I did choose Dr Kim because of more published examples of good results, which is what really mattered to me, and is something Dr Haben explained why he would not provide. I did not find that explanation very comforting, but I can see his point of view.
In the end, we both will likely end up with good voices, no matter who we went to. 🙂