Butane cooks longer than propane based on same volume. Easier to connect using clip style connector vs. screw on. Butane has about 12% more energy than propane by volume.
You can cook longer with butane than propane, it's also not as toxic. Butane is less expensive than propane. However propane is more popular and easier to find.
Usually butane is less expensive to purchase than propane, when using the same amount of fuel butane will generate approximately 12% more energy than propane because it is technically "more efficient."
