Pex started to be used in Europe in the 50's...one of the original manufacturer's was Wirsbo (Uphonor now). There's over a billion feet of the stuff installed. There are three (that I know of) manufacturing methods producing stuff in types -A, -B, and -C. Wirsbo only makes -A. Some manufacturers may not have been making it for long, or just put their name on it made by someone else. As a result, they have little history...but, as a product, assuming you get it from an established manufacturer and install it properly, it works long-term. Fail in quality control or manufacturing technique, and any can fail. Uphonor not only manufactures the tubing, but the raw materials as well, so they can control their quality all the way through the process. Type -A is the most flexible, the smallest minimum turn radius, and the only type that can be restored if it gets kinked for any reason...the others require you to cut out the kink and insert a fitting. So, you not only have choices in type of material, you have to pick a quality manufacturer.
