Whether you think Infernal affairs or the Departed was better depends on which you watched first, and whether you are fluent in the languages.

Rating: 7/10 (11 November 2006)

I watched Infernal Affairs when it came out. I thought it was a really good movie, with an original plot, and great actors. I watched the Departed a few days ago. I think to appreciate each film, despite some people saying that the language barrier doesn't matter, I think its a major component. Some people applaud The Departed in that Scorcese portrays the American setting really well. Well I can't appreciate that because I'm not from there.
ALSO a big part of appreciating the movie is letting the plot unfold without knowing what will happen. I watched Infernal Affairs first, so naturally when I saw a lot of the plot and even minor details copied from the original, it raised an eyebrow and hindered the flow of the movie. A lot of things, like the plastered arm and envelope with the crossed out spelling.
Another thing I like in Infernal Affairs over The Departed is that it has more contrast in emotion. There are moments of comic relief by the "Sor Keung" character, and, for example, DiCaprio's character in Infernal Affairs isn't yelling and punching people the whole time. The Departed has a bit too much violence and swearing to my liking, even if that is an accurate portrayal of what people were in that setting.
To be honest, the biggest determining factors in people's preference of the movie is which you watched first, and which language you are more comfortable with. I watched Infernal Affairs first, and though I'm fluent in both English and Cantonese, I appreciate the cultural background of the Hong Kong version more. All in all, I can't really judge which movie is better than the other because I'll probably be biased, but I certainly enjoyed watching Infernal Affairs more.