Despite using Grohe at home, I would say in this case, Panasonic is better since it would provide you warm water for shower.

Shower system without mixer & storage water heater is useless.

Grohe. warm water is for pussies. Cold water exposure increases testosterone production in men, presumably as part of our “flight or fight” response to perceived danger. Not only is your testosterone level responsible for your virility, it’s also a vital component of muscle synthesis. So a cold shower after a heavy gym session should help you grow.

even for cold shower best is start with warm water then slowly turn off water heater.

start with cold water during rainy day is torture.

A normal cold will be helped by a cold shower - heightened metabolism stimulates the immune system.
some people cannot take cold shower

they can get sick from the flu

TS posted set of handheld shower and overhead shower only. There is no mixer in the photo. And TS still need to buy mixer and storage water heater.