I've seen The Departed a few times, and I think it is a good movie.
However, I've heard that people say Infernal Affairs (the movie The Departed was based on) was much better, and honestly, I have to disagree.
First of all, I'll say this: Infernal Affairs had poor pacing, poor editing, poor directing and underwhelming acting, especially compared to The Departed.
1. The beginning of Infernal Affairs goes at lightning speed, not giving you enough time to feel compassion for the characters, or understand them.
2. The 'boss' of The Triads in Infernal Affairs had nowhere near the charisma of Frank Costello, neither was he nearly as intimidating. In The Departed, Frank is unpredictable and ruthless, you want him to be taken down. When I watched Infernal Affairs, I didn't care.
3. The therapist plot in Infernal Affairs was barely touched upon. There was no powerful scene like the 'valium' scene in The Departed. I did not feel much chemistry.
4. The intense scene where Leonardo DiCaprio is discovered by Matt Damon to be the rat, is completely forgettable in Infernal Affairs. As the mole calls the rat's cellphone, he says 'So it's you?' - I was not on the edge of my seat. In The Departed, Matt calls Leo - Leo hangs up. He has no idea what to expect.
5. People criticize 'The Departed' for Martin Sheen's death and Leo's cold reaction.
However, The Departed never makes Martin Sheen a father figure to Leo. This is the worst scene In The Departed, but it just seemed corny in Infernal Affairs.
6. Tony Leung (the rat) feels he is 'going psycho' in Infernal Affairs. However, this was not portrayed well at all. In The Departed, Leo's character is thrust into a world of violence. He witnesses beatings, murders, and in the film you can actually see he is at the breaking point. You can see how it affects him, how it makes him feel.
7. The climactic scene where the rat is suddenly killed while exiting an elevator, was corny in Infernal Affairs. After he is shot, sad music plays, and there are close ups of faces in black and white, in slow motion. In The Departed, it is completely abrupt. The protagonist of the film has just been killed, but the film does not make a big deal out of it.
8. Another scene is the rooftop scene. The rat encounters the mole. In Infernal Affairs...there is hardly any emotion. It's not exactly an explosive encounter. However, in The Departed, Matt Damon knows what he has done, he knows he has been led on. Leonardo has gone through hell, and now he discovers the truth. There is plenty of intensity.
9. Infernal Affairs glosses over the therapist discovering the truth about the mole. There's just some text at the bottom of the screen telling you what happened. In The Departed, the therapist plays the tape given to her by the rat on the speakers.
10. I hear people talk of Andy Lau's performance in this film, but Tony Leung did a better job to me. However, neither were on the level of Jack Nicholson or Leonardo DiCaprio.
11. Infernal Affairs does not tread into the 'criminal underworld' enough. The Departed shows you a good deal of what's going on behind the scenes.
My biggest criticism of 'Infernal Affairs' was that it seemed cold and robotic. The Departed was electric and intense.
Infernal Affairs elevator scene: https://www.youtube.com/watch?v=k-SOciCRCdo
The Departed elevator scene: https://www.youtube.com/watch?v=b66y1LHixqY
Nothing in Infernal Affairs entertained me like:
Leo meeting Jack in The Departed: https://www.youtube.com/watch?v=z-gCd2vXziY
Leo encounters Frank Costello for the first time. Frank's intimidating presence immediately comes across in the film. You can see why he is such a big deal, and why he has to be brought down. This scene portrays the 'lion's den' Leo is entering.
The valium scene: https://www.youtube.com/watch?v=aHknTd29GEI
In this scene, Leo expresses his anxiety and how his criminal life is affecting him, without mentioning he is undercover. You understand how difficult his job is.
I'm not saying Infernal Affairs is a bad movie, but that it's definitely worse than The Departed. Infernal Affairs has good framework, The Departed just does it better.