For all that, I’ve become convinced that the ultimate water pipe system, is galvanized half-inch cast iron. In this old cow town where the homes were mostly built grudgingly and inexpertly by farmers wishing they were on a tractor instead, two or more generations ago, the one thing most of them did totally right, was to use galvanized.
It only works in assemblies consisting of straight lines and right angles, you have to strategize about the sequence of installation based on turning successive elements clockwise to tighten them, and almost inevitably you have to thread up specific lengths to fit the circumstances, on a big thread-cutting machine which usually only plumbers and hardware stores have.
But they never leak, they can freeze and thaw out and never break in the process, they last decades (most of the homes I work on have pipe set in the 1960s or before), and they have the additional convenience of being able to run ground wires to them from the electrical system, in a town where maybe nine out of ten houses were never wired for grounding to begin with.
I doubt I’ll ever get to install one. The pex is so easy, fast, and affordable, and makes routing the lines far simpler than any other kind of pipe, that it’s doubtful any client would ever want to go the galvanized way. But those who have homes piped with it, swear by it and for good reason.
My big thing is red and blue pex for hot and cold water respectively. Even when most of the lines will be concealed, it is a big asset for what the old fellers taught me years ago about consideration for “the next guy”. I get a big kick out of a finished system with those pretty colors and everything laid out nice and neat. One can enter the system at any point such as punching a hole in a wall to add on a tee to extend the system for a new fixture, and see at a glance which is hot and which is cold, which can be a more vexatious dilemma than you might think sometimes.