Which is the better option for shower? IPS or CC? How would I know which is correct one to use?

Hi Smd...

Are you asking about IPS vs a copper x copper shower valve? If so, copper x copper usually results in less work because you can transition to the existing piping with fewer joints.

What kind of piping is in place now? Copper? If so, then go CxC. If galvanized, I'd back it out to the nearest accessible joint(s) and install all new copper piping to the valve... again going with a CxC valve.

Let me know more on this...

MARK