Most people I know swear by what they are doing. I swear by spinning of course. They are certain they are doing the exercise that is burning the most calories and it works best for them. I always have people telling me I should change from spinning to some other form of exercise.
So what is the truth? Am I wasting my time spinning? Is it time to sell the spinning shoes in a garage sale? Not so quickly.
Everyone can benefit from exercise. No everyone is perfect for spinning. Not everyone can box or do aerobics. By all means, everyone should be doing something. Not child should be sitting in the couch all night long. Even older people should be doing small things such as arm raises and leg raises while sitting.
But what actually burns the most calories? Here is a look at what exercises burn what amount of calories for 1 hour of activity:

The winner is….step aerobics. Step aerobics burns about 900 calories every hour. Very good exercise. Spinning, running and cycle racing come in a close second. Nearly 800 calories per hour can be burned in any of these exercises.
I prefer spinning over aerobics simply due to control. I can control my heart rate very easily when spinning. Workouts can be tailored to hit certain heart rate zones that can provide a variety of benefits. Although aerobics are a very good exercise, it is more difficult to control your heart rate in to a specific zone.
Again, any exercise is better than no exercise. If you want the best heart rate control in a class that is really enjoyable, spinning is your answer.