I recently purchased a 44'' bellicon. I went back and forth between the 39" and the 44". It was not so easy to understand the difference between the sizes especially when I had never been on a mini trampoline before. I did get the 44" model and I am very happy with it. It does give me extra room for my legs if I want to jump high or jump wide. I am 5'4" 130lbs and I think the 39 probably would have been fine for me though. So, if you have a space concern or want to travel with your bellicon, bigger does not mean better. I am a yoga instructor and have loved my yoga practice for many years as my main exercise. As I get older, I need more cardio for my state of mind as well as my body. I love how I feel after a session on my bellicon. My body feels light and vibrant and my mind feels very clear. I love to ride a bike or walk, but this is a very different feeling in the body and much kinder to my imbalances. I get no residual pain. I am grateful for my bellicon!!