For me, above the neck is the big difference. They both had some really good victories but Nelson was always competitive until his "final bout" in the trilogy against Leija. Norris had a few issues with his chin and he was DQed three times for illegal acts. Norris could be more spectacular and more entertaining but The Professor was definitely the greater fighter.
Nelson hands down. I think Norris was one of the most athletically gifted fighters that I have ever seen but he would often neglect defense and who could forgot the bone head fouls/DR'S. Nelson on the other hand, was a true pro's pro.
It is not a landslide and I would say for a short time Terry was at the very top in the boxing world where Nelson was more solid overall Terry went to greater heights.
And what’s even worse….is that if these two fighters were in the same weight division ….Azumah Nelson would be worst possible opponent that you could put Terry Norris in the ring with