The answer to 'which is better PEX pipe or copper pipe' is that PEX pipe is generally considered better for most residential plumbing applications. PEX (cross-linked polyethylene) pipe offers several advantages over traditional copper pipe, including lower cost, easier installation, and better resistance to freezing and corrosion.
PEX pipe is more flexible and requires fewer fittings, which can reduce labor costs for installation. It is also less prone to leaks and is not affected by corrosive water conditions like copper can be. PEX is also a better insulator, helping to maintain water temperature. On the other hand, copper pipe is more durable and has a longer lifespan, but it is more expensive and labor-intensive to install.