The main problem with these systems is they use a tiny o-ring to seal on the outer surface of polybutylene pipe. But this pipe is soft and is easily scratched, and if there is a scratch where the o-ring is seated then you are going to get a leak. Other systems such as old-fashioned crimping, seal on the inside surface of the pipe, which obviously not likely to be scratched. The other problem is the quality of products. In many cases it is just not practically possible to push the pipe into the connector because the grab-ring teeth are too tight. Then you have to dismantle the join and pull out the grab-ring and either replace it, or use long-nose pliers to adjust each tooth so that you have a chance of pushing them over the pipe. Arghhh! What a waste of time on a system that is suppose to speed a job up.