Easy to assemble, easy to balance on. I was experiencing back problems from sitting in a chair all day. This ball helps relieve pressure on my back and keeps me moving unconsciously while I work. This chair forces you to engage your abs and I now have a two-pack just from sitting on this for a couple of weeks :). I like how this looks much cleaner than a stability ball and blends in well with the office environment. Additionally, this is great if you are a skirt-wearer because I can use this while wearing a skirt and could not use my stability ball. This also requires a lot less attention than a stability ball and I can concentrate fully on my work. Highly recommend!