It's grainy plastic that's not very pretty unless you take the black leather seats. It's a personal opinion and I'm not asking to agree with me.
If you have the seat backs painted in body colour then they are a smooth composite/plastic as in the picture at the top of this thread. I had mine covered with PPF - see my other post in reply to Gaston.
I had the backs of the seats painted by a bodybuilder. it cost me a quarter of the price of the option. I didn't think of the PPF movie. I will do it because the paint is fragile. Thanks for the advice.