In the begining i found this difficult to use and the more i used it the better i got at it and i could feel myself get stronger. My fiancee used this as well and it really did a lot for his abs, they looked fantastic. I however am not as cordinated and fell off this many times and landed just right and hurt myself. The knees are very slippery on this and easy to fall off so i stopped using this after being hurt a couple times. Performance If you are able to hang on and stay in place this has great perfomance results. Ease of Use It was difficult to use in the begining based on my lack of strength but with time it got better and easier Durability So far no problems with anything breaking Design with the exception of it being way sliipery and easy to fall from the rest is a great design.