Not personally but a livery on a previous yard had to get her horse denerved due to pedal ostitis. However for whatever reason it didn't have any great effect and the horse was put down. I know if the horse is being denerved for a foot complaint (this might be the only reason a horse is denerved - I'm not sure as I'm not a vet) then you have to be incredibly careful with regards to its feet. If it got a nail through the sole for example it would not feel this and all sorts of problems could result.
Just be guided by what your vet says than popular opinion. i think you will always get an honest answer if you start the dialogue "if this was your horse what would you do?"
Haven't heard of a horse being de-nerved for years! I would want a second opinion. In my experience, it is seldom successful from the point of view it removes the feeling in their feet therefore you get problems with tripping and it is not pleasant jumping anything solid as they are quite happy to hit it hard! I would not have it done!