I’ve had glottoplasty, and I know quite a few other folk that have too. And it can make a huge difference. But other people say that it changed their pitch, but that they aren’t happy with the results.
And from what I can tell, the difference was largely related to whether people had done voice training or not. Those who had done training seemed to find that VFS was a big help in getting them across the line, but those who hadn’t, tended to find that their results were more “meh”.
The way I put it is that VFS improved the instrument I was using to speak, and let me get more for less with my vocal training.
The downsides for me are that I can’t project my voice very well anymore. I am regularly told that I am softly spoken, and I have trouble being heard in clubs and busy restaurants. But I can shout and sing just fine. It’s only projecting a speaking voice that I struggle with.