The copper vs PEX decision is not one I took lightly...copper has the supposed longevity...but the disadvantages add up. The PEX is a plastic...and that gives some folks pause...but I believe if it's kept out of the sun it will be fine (much like PVC pipe, that we've been using for years now without issue).
Last year I paid $4000 to have my foundation jackhammered up and the copper replaced (hot water line to the guest bedroom). This was in my 80's tract home. Seems we ended up with some sort of electolytic action going on and it corroaded away. I did this after my utility bills went over $500/mo on the leaking hot water.
My insurance company paid the additional $3000 to jack the slab back into place where the mud settled under it, but wouldn't pay for the labor/repair for the leak itself.
And that was the good stuff. Have you seen the copper pipe today? Comes out of China and is about half the thickness. It's also wicked expensive....and as I mentioned...I don't want 'em to burn my house down crawling all around under it and inside walls making joints. As one that's used copper before, I also have reservations about the solder now...long term corrosion/etc after they took the lead out...but admittedly nothing but my gut to back that up.
The plastic fittings were problematic on the poly pipes in the past, hence why these systems weren't code approved anyplace around here (they used them in mobile homes...there were lawsuits). Those weren't manifold systems...and had many, many fittings under the floors.
I don't believe the new crop of fittings will ever fail (without help...improper secured, too much tension/ect). They are extremely tough, with stainless components...and there won't be very many of them in the system, which is to me, a cool advantage. In my experience, most plumbing issues are at the joints.
In my new (LOL very old) house, there will be no fittings except at the manifold and the fixture. None whatsoever underneath.
BTW...this "upgrade" is from lead pipe and galvanized iron...both technologies that were "the cat's meow" at the time. It's time to move on again.
We'll be using PVC in place of the cast-iron for sewer lines.
