It can be a local situation. In Phoenix, the CPVC is installed in the attics and when it gets hot, the fittings can fail occasionally. And since it is in the attic, the cold water supply is always hot in the summertime. Copper is installed under the slabs so the water in is remains cool. In your area, copper and plastic might both be installed in a basement or attic, so that would not be a consideration for you.