My husband had his name legally changed before we got married. He was named after his very abusive, alcoholic father, and the legacy of being his "junior" was something he needed to symbolically throw off by changing his first and middle name. He still has a visceral reaction when for some reason his birth name comes up (sometimes does on legal matters, etc.)

You have to go through the court system to have it done, but it wasn't a terribly long or difficult process. Of course, then you have to work on getting all of your documents, accounts, etc. changed, but once it's done, it isn't a problem.

He did have some push-back from his family, but he just rode it out and they eventually caught up with it and got over it (at least outwardly). There may be lingering resentments, but he long ago broke off contact with most of his family anyway, so he doesn't particularly care.