We have just begun using Prep U in Med/Surg Nursing. I love the product as noted above for its question format and rationale and do believe it is superior to ATI, BUT, big but, we have not had a class graduate as of yet to effectively evaluate it against ATI. Our students have done well on the boards with ATI, and the first Prep U class will be taking the boards in the spring. If you are considering the change I would wait until there is more data on Board Success.