For me, it's the most fun. He golfs, but also includes in his routine three other activities. I also use the Stairmaster, but I think there's too much movement. Of the aerobic exercises, I think the treadmill is the most fun. I can read or talk with the person next to me, and I like the social aspects of it.
Golf is truly the most fun.
Today, Moore walks on occasion and lifts weights. When I walk, on the other hand, there's continual stimulation by what you see as you move along. I like that because it distracts from the effort I'm making. Obviously the choice is strictly personal. So maybe it doesn't matter how many calories you burn as long as you're having fun while exercising.