With PEX B doesn't the fitting reduce the flow as it's ID is smaller than the ID of the pipe?Both are used by professionals, is wha I was getting at. Pex A is "expansion" type, and B is crimp style. PEX A can be crimped or expanded, B is crimp only. They both have their advantages and disadvantages, and one is really no better than the other. I really depends on the system and its requiresments.
Alot of PEX A has to do with liability of installation. PEX A cannot be connected, unless you expand first. PEX B on the other hand can be fully assembled, and even tested, without being crimped. Over the years, many people have flooded houses and buildings with uncrimped joints. Simply put, with PEX A, you cannot......not connect it.......if that makes sense.
A plumber who has done some work for me says the quality homes he does the plumbing for are either copper or CPVC. The big developments that want things done cheaply use PEX.