am i a bit late?
anyway i have changed nuts just on two guitars... one because it was a cheap looking and feeling piece of plastic, the other because i blocked the trem and got rid of that useless locking nut, so my luthier used a graphite one...
i've got an earvana on my LTD EC1000, and i can say that it doesn't wonders. the 3rd string goes quite easily out of tune, even if i've got locking sperzels... i'm not sure if it should be supposed to keep intonation better than other nuts. if yes it's a failure!