Not that my personal experience is relevant, but since you did ask, I endured many years of hell. Its one of the things which got me thinking about forgiveness, long ago. Abuse I endured in years past has had permanent impact, but I forgave it long ago and feel no anger or resentment towards it. I just see it as another thing that's happened in my life. That hell I endured, is part of who I am, just like every other experience is. I found good in it even, mostly in the form of resilience. Even more good, is that I see all the incredible things I've been so lucky to experience in years since that ended, and realize in a weird way, had all the terrible things not happened, maybe I wouldn't have had those great experiences. Just by the flow of life, maybe I'd of been elsewhere. So in that way, I even have a sort of gratitude for what happened, for indirectly bringing me to moments later on, that I cherish. That's just how I see life.
Forgiving and showing kindness to the person who did these things to me, had an impact, I believe this. Maybe receiving this kindness and forgiveness, will stick with them, and they will be less likely to treat another in that way when the time comes. Maybe it won't. But I know, had I responded with hatred and anger, they probably would have just felt justified in the end. I feel no anger of what has occurred and wish no suffering on that person.
That said, I've realized, there is a delicate balance. Forgiveness and kindness, I will always support this. But it's also good, to let a person understand the impact of their actions. Else, they might mistake forgiveness and kindness for thinking they did nothing to hurt.