We really liked the nuk bottles. Our daughter would not use any other bottles after using the nuk orthodontic bottle . We chose nuk bottles for three reasons. Two of the reasons were based on the shape of the nipple. We liked the idea of the nipple helping from an orthodontic aspect. I liked the idea of the shape of the nipple helping for nursing moms. I believe it helped my daughter with the adjustment from switching. I felt a lot comfortable using a bpa free bottle also. I would of used glass bottles if it wasn't for the bpa free plastic bottle. They always have great designs for there products. I love seeing what new items they come out with. I always look to nuk for all my babies feeding needs. I will always recommend nuk orthodontic bottles and any other products they have. Leak Prevention If my daughter would grab the side of the nipple it would collapse in sometimes and begin to leak.