Many people would answer this question without really thinking too far into it. Most people would think this has any obvious answer. Why, of course the person being forgiven reaps more benefits than the person that forgives. To be forgiven holds a feeling of satisfaction, people might say. Nobody likes to have grudges held over their head. These arguments are generally true. But what about the person that does the forgiving? Don't they have any benefits at all?
I'd like the analyze this question in terms of the novella The Body Artist, written by Don DeLillo. Throughout the story, the main character, Lauren Hartke, is dealing with a number of issues that she must overcome. One issue that she faces is dealing with the suicide of her husband, Rey Robles, and trying to forgive him for taking his life. If Lauren is trying to come to terms with and forgive someone who is dead, would the person being forgiven reap more benefits? Probably not. Lauren is trying to forgive Rey, not to help him, but to help herself move on with her life. The second issue that Lauren deals with is trying to forgive herself for her mother's death. Lauren's mother died when she was nine years old and although Lauren is now a grown woman, she has never been able to convince herself that it wasn't her fault, an issue that most kids who deal with death face. Again, forgiving herself would not benefit anyone other than herself. Also, the fact that she is forgiving herself is just going to help her move forward in life, it is not actually going to give her the satisfaction of being forgiven like everyone else always assumes. At the very last scene of the story, Lauren throws open a window in a room, an act that can be interpreted as moving on and moving forward, an act of readiness to come to terms to with everything. Lauren, in this scene, is finally able to forgive Rey for leaving her and herself her mother's death. This is the only time when the benefits of forgiveness are actually shown in the novella and it only shows Lauren's benefits, or the forgiver's benefits, not the forgiven's benefits.
So, who does reap the benefits of forgiveness? I think it safe to assume that Don DeLillo, based on his novella The Body Artist, would say that the forgiver reaps the benefits.