1) The movie took the important parts of the comic and stripped away all the unnecessary stuff. I tried reading The Crow and found it to be inferior to its adaptation.
2) The production design was fantastic, including the scoring of the film.
3) A tremendous ensemble cast of great character actors, and Brandon Lee in a role that he absolutely understood and was able to perfectly communicate to the camera.
That said, people do tend to overrate The Crow because of Lee's death. It's a great little supernatural revenge/love story that still holds up, but some people really put it on a pedestal.