This is one of my favorite films of all-time. Bill Murray is excellent as the lead in a dramatic movie, much to my surprise. I think his performance in this film is every bit as good as his work in "Lost in Translation." Murray is far more flexible as an actor than he usually demonstrates or is given credit for. He is more than just a comedian.
The failure of this movie at the box office rests squarely on the shoulders of Paramount. They gave this movie so little support or advertising money that it was almost doomed to fail. To be honest, if the internet and IMDb had existed back then, the coast to coast word of mouth that could have been generated might have made this movie a winner at the box office.
There is a story about this movie that I once heard. Murrary had read the book and the script by Byrum, who also directed. Murrary approached the studio and told them he wanted to make this movie. The story goes that they respond with, "Sure, Bill, we'll make The Razor's Edge for you if you will make this little movie called Ghostbusters for us." He agreed and Paramount technically stuck to the deal, but they put no money into its promotion and it dead an untimely death.
This is one of the great films of all-time and it is just a shame that more people have not seen it.