Well, it depends on what you like. The movie is very visual, with great stunts and cinematography. The novel, on the other hand, can go more in - depth into John Wick's thoughts and emotions. It's exciting in a different way. You get to understand his motives better, which makes the action scenes even more engaging.
Yes, it is said to be loosely based on true events. There are real - life assassins and the world of the criminal underworld which might have inspired certain aspects of the movie.
The 'John Wick' movie has elements that are based on real - life ideas. For example, the underworld criminal organizations and their hierarchies that are shown in the movie can be related to real - life organized crime groups. Also, the concept of a lone wolf figure like John Wick, who has a particular set of skills and is feared by others, is something that can be seen in the real world in the form of highly trained operatives or individuals with a dangerous reputation. However, the movie also has a lot of fictional elements like the elaborate assassin's world with its own currency and rules that are exaggerated for entertainment purposes.