Weight lifting versus cardio, which is better for losing weight quickly?

Weight loss. Cardio. However rapid weight loss is usually not desirable. Better to have a healthy life style and loss excess weight more slowly and then keep it off.
Both of course! While cardio has always been associated with weight loss, the advantages of strength training are increasingly becoming known. Strength training increasing muscle mass, increases metabolism, and also increases the efficiency of the cardiac exercise. But you gotta burn calories as well, and cardio is a rapid efficient way to do that!