There were two versions of Episode 4. In the first version, Which came out in 1977, Han shot first, And then they edited the original in 1998, And it is obvious that Greedo shot first. I personally have not seen the original version, But the "special edition" is just a complete insult to the people at ILM that worked on the film in 1977, So it, By default, Is better. HAN SHOT FIRST.
If Greedo shot first, Han would have died there. Then the mess that is episode 8 would have never existed. It was edited to make him look more innocent, But that is why people love Han. He is a smuggler that hangs out with unsavory people. That was a preemptive strike that saved his life.
Han Shot First First, Greedo Shot First Second. By that I mean when they came out with a new, Edited version of the movie a few years later they made a millisecond change and when looking at it frame-by-frame, Greedo shot first instead of Han. It was a ridiculous change but it's kinda funny how angry people will get over this.