This is an amazing set of four great movies and for a decent price. "Dial M for Murder" appears to have been remastered, and cleaned up, and really looks fantastic. The colors are rich and vibrant and the blacks are deep. "The Big Sleep" though, is not remastered, and has dust spots on the negative. Also, the left side of the frame sometimes appears dull and lacks the deep blacks seen on the right side of the frame. "The Postman Always Rings Twice" also has dust spots, though "The Maltese Falcon" appears to be clean.
I was surprised to also see that each film has many special features, including interviews with other directors, film historians, or archival experts. The packaging is basic but it does the job with a movie on each side of two discs in a DVD case. This set is an excellent buy.