This ball is great for me because I have a bad knee (soccer), I can do all types of exercises on it, not just yoga, that get me great results without the bad pain! It is good for people who are just getting started because there are a lot of simple exercises to do, and as you get more experienced, the more complex you can make your routine. Besides that its easy to store in a closet and easy to inflate/deflate if you're going to have company over and need all the space you can get!
Yoga Balance and Exercise Ball is recommended by AmandaLynnFike