We'll have to agree to disagree on that Kev, all the ones I've seen have shown signs of the finish degrading in roughly a year, including my own. If you look closely it'll have lost its sheen and become brittle and blister. Might look fine from a distance.
Problem with alloy it that when it gets warm it 'gasses' out and starts blistering. That's why you need to preheat it before powder coating otherwise it comes out looking crap.
Our engines run hot and constant heat cycling degrades it.
I'd advise anyone that wants that super fresh painted look to last for a good few years, not to powdercoat cam covers and turbo pipes but find some other alternative coating that can handle high temps. It's fine for other odd brackets etc.
I'm not too sure about NA cam covers as they're a magnesium alloy, I've not had any experience of powdercoating that.
Just my opinion and advice of course.