For pipes, I would always choose copper over plastic, regardless of the price.
All the plastic pipes that I have ever seen had a too short lifetime, and when it became necessary to replace them prematurely in whatever hard to access place they had been installed, the costs were much higher than the cost of the pipes.
Even if the plastic pipes were claimed to be made of some high-quality long life plastic, instead of being made of cheap PVC or the like, such claims are difficult to verify, unlike for a copper pipe, where you do not need special instruments to verify that the pipe ready to be installed is really made of copper.
All the plastic pipes that I have ever seen had a too short lifetime, and when it became necessary to replace them prematurely in whatever hard to access place they had been installed, the costs were much higher than the cost of the pipes.
Even if the plastic pipes were claimed to be made of some high-quality long life plastic, instead of being made of cheap PVC or the like, such claims are difficult to verify, unlike for a copper pipe, where you do not need special instruments to verify that the pipe ready to be installed is really made of copper.