I've had mine done for 5 years now. Certainly lasts and certainly works, it was done by Zircotec. I had the performance white I think. The colours are definitely a secondary benefit, and yes it definitely helps with heat management in the engine bay.

It should also help contain heat and enhance the scavenging effect of the exhaust gases and that's where they claim the performance benefit. I reckon it also prolongs the life of a stainless steel exhaust manifold by reducing the risk of cracking.

There is a reason why some of the top motorsport series and companies use Zircotec.