Martin Scorsese is one of the great directors of our time, but The Departed is not his best film, not by a long shot. The Departed would have to take a backseat to GoodFellas, Taxi Driver, Casino, Gangs Of New York, and Raging Bull. Hell, you could make a case for Hugo being the better quality film over The Departed.
Face it, when it comes to Scorsese's greatest hits list, The Departed is bottom of the barrel at best. And The Departed's 2007 Oscar win for Best Director was a pity prize for Scorsese, because he was screwed out of that award in 2003 (Gangs Of New York). Letters From Iwo Jima was clearly the better film, and Clint Eastwood was the better director.
When it comes to crime dramas, The Departed has some tough competition, but Sin City is a one of a kind film. Frank Miller tried to recreate the same magic for The Spirit, and the end result was a colossal failure.