Which Workout?

The effectiveness of aerobic workouts depends on intensity and duration. As long as you get your heart rate into a training zone, any form of aerobic workout will have the same effectiveness if maintained for the same time. So you can use any type of exercise you enjoy, or go from one aerobic workout mode, or one machine, to another. No type of aerobic exercise is inherently better than the others. Your heart doesn´t know the difference.