I think that the experiment was good for Charlie for a few different reasons. First of all Charlie was able to experience life as a normal individual. As he became smarter he was able to talk intelligently to others. He was also able to experience attraction to another individual who was Miss Kinnian. He knew what it was like to have a below average intelligence level and he also discovered what it was like to be a genius.
There are also some negative aspects to this question as well. Charlie regressed. This was very difficult to experience. He went from being way below average to way above average. He had to deal with this. This must have been very frustrating and heart breaking.