EVGA may be Nvidia only but that doesn't stop ASUS from producing some ground breaking cards their either, a perfect example is their MARS III card ( a dual 760 on one PCB) even Nvidia hadn't made a dual 760 and neither had EVGA, don't just fall for the assumption a manufacturer dedicated to one companie is better than one that caters for many.
I thought about writing up a long, detailed response to your points, but figured there's no point. The fact of the matter is that the cooler on the ROG Matrix is fundamentally not suitable for cooling the R9 290x's Hawaii GPU. I don't know why you brought up other cards which are not at all analogous to the ones we're talking about, or watercooling for custom PCB cards which are not geared towards watercooling because you have to take off the cooler, so you're paying a premium for just about no reason, but none of that is relevant. I've given you evidence which shows that despite all of the superfluous features the ROG Matrix has, it still cannot perform as well as the Vapor-X when both are overclocked to its limit. in most cases, it performs about as well overclocked as the Vapor-X does at stock levels. They're both the same price as well. The Vapor-X is the highest tier of aftermarket R9 cards you can buy.
As far as EVGA being superior because it is Nvidia only, there are multiple reasons for why they make the best Nvidia cards, but it doesn't seem to matter if I tell you them because you'll just assume I'm blindly supporting the company because they're exclusive to Nvidia.
And with that, I'm bowing out. There's no point in getting hostile over something that is really irrelevant at this point, because premium 290x's are becoming obsolete.