I am 53 and moderately active. I have the 44" classic. Start out with short spurts! At first I jumped for too long because it was so fun. It was like I shook up my organs and everything hurt inside. (in a post workout kind of way). When I started more gradually, it was fun and easy and no longer "shook me up". Lightly bouncing on the Bellicon helps to adjust my mood after a stressful day.
When I do intense work outs, I will use the Bellicon for some of the exercises to decrease the impact on my knees. I'll jump on it when I don't have time for a full workout. Even 10 minutes is enough to get the heart rate up.
Great quality. Quiet. Fun!