Three genuinely different jointing methods and three genuinely different limit curves — the "right" supply pipe material is whichever one matches the run, not whichever one is newest.
Ask a plumber which water supply pipe material is best and the honest answer is "it depends on the run," because PEX, copper, and CPVC aren't three tiers of the same product — they're three different materials with three different jointing technologies, three different failure modes, and three different sets of code restrictions. Copper (rigid, soldered or pressed) has a fifty-plus-year proven track record and resists bacterial growth, but it costs more, corrodes in aggressive water chemistry, and has real scrap-theft value on job sites. PEX (flexible, crimped/expanded/push-fit) installs faster with far fewer fittings and tolerates a freeze-and-thaw cycle better than rigid pipe, but it can't see UV light and isn't chew-proof. CPVC (rigid, solvent-welded) undercuts copper on price and handles higher temperatures than ordinary PVC, but it can turn brittle with age or certain chemical exposure. None of the three is a strictly dominant choice — each wins on a different axis, and the actual design decision is which limits the specific installation can live with.