I bought this exercise ball primarily as a computer chair, as I tend to slouch in my desk chair. I now swap between the two (I'm sitting on the ball as I type this) and due to its large diameter it works quite well. Not only does it improve my posture while I'm on the computer, but it only takes seconds to scoot back and do crunches, so it ought to improve my core strength as well. It does have a strong chemical right out of the box, but I washed mine with hot, soapy water and aired it out in my backyard and garage for days at a time to combat this. It's been a few weeks now and while still present, the scent is noticably less strong. I imagine it will become negligible within a few months. It holds air fairly well, requiring topping off only once a week or so with regular use. All in all, a very good value in my opinion.