Running burns a larger percentage of carbs, but more calories are burned overall. Lower intensity exercise causes more cals to be utilized from fat. However, since fewer carbs are being used, there is a better chance for the carbs to be stored and possibly turned into fat later.
With no change in diet, I've noticed I get leaner, faster with running than any light-intensity cardio.....most likely due to the fact that i'm burning a greater amount of calories.