This exerciser was an impulse purchase after seeing a very inspiring infomercial. It cost a pretty penny, but it has been worth it, because I can exercise indoors every day and not suffer any back strain. In fact, the selling point is that the position you are in plus the action of rising and falling along an arc tones the waist and abdomen without stressing the back. I find that to be very true, as even if I exercise a long time, I never have back pain. Another good point is that being able to exercise like this indoors satisfies an important need here in Phoenix, where temperatures from May through October can easily reach 100 degrees outside, making exercise just not happen for many of us. And having this exerciser here where I may exercise as much as I want whenever I want is a good substitute for an expensive gym membership. Performance I feel my muscles being used because my abdomen and waist become warm, and I have seen myself trim down enough to be able to see the results when I wear a swimsuit. I do not become starlet buff, but I feel good and look good, and this exercise is pleasant enough to make me look forward to it as part of my daily routine. Ease of Use Exercising is very easy with this device because all I have to do is kneel onto its seat and grasp the handles and slide myself up and down the arc. Durability Mine has lasted well for 7 years and is still good. It's part of my daily routine. Design I find it innovative. To be able to slide up and down in an arc is great for exercising quietly and in small spaces. It's very clever because I can twist and swing the seat around while rising up and down the arc to make side muscles exercise too.