I had our rooster done by this vet and I found him to be a caring, kind person. He gave care advice for the immediate aftermath, which we followed to the letter, and also suggested that I keep the rooster confined such that he couldn't stretch out his neck in order to allow the changes to heal in place without crowing. He suggested 3 weeks, we did it for 2 weeks, kept him indoors in a crate. We also did the aftercare instructions very carefully. Our rooster healed up beautifully. His voice did return eventually, but it was always WAY softer than it had been and our neighbors were able to live with it. This vet has always said that the voice can come back, so I don't view it as a "FAILURE" but just, the risk is that the voice isn't gone completely. That was always known. Also if someone doesn't take care of the rooster medically afterward, the risk of dying is real.
So the person who posted who said they had 13 roosters either fail or die, well... there's no telling whether those roosters got proper care afterward, and if you didn't do the crating/isolation the risk of the voice returning is even higher, but the risk of some return is always there.
I remain very happy with our experience.