I"d lean to Pex hard right now. The only thing is we don't know how it will be in 30 years, but so far its been good.
Be warned in cold though, the fittings themselves can freeze and crack. The pipe will not.
Copper is good IF the water doesn't eat it away and todays copper isn't near as good as 50 years ago.
CPVC is ok today, but damn stuff gets brittle....with age. My attic is full of it. Ugh. One day I'm considering attempting to repipe. But I have other more important stuff right now.
