Pex is fine. The problem comes in people doing shit installation or bad crimping. In the picture I posted, whoever did the pex in that wall should've known better. If you crimp pex, the line will have to be under some absurd amount of pressure before they give out and it's the pex line that will burst, not the crimp seal. As for wear and tear, it's a tube of plastic in your wall. It'll last until the end of time or until your replace it. If you use an RO system though, that puts a strain on every kind of pipe but still, pex is good for a long, long ass time.