In PURE GAMING TERMS, there is NO argument - Intel is king.
If you have the right graphics card, at the right resolution, with the right games...it's the king of gaming benchmarks. It's also meaningless if you can't tell the difference when you are gaming. I'm betting YOU wouldn't be able to tell in a blind test. In the long run, I'd also bet that more gamers will feel the 40% average loss in multi-threading on a 9900K worse then they feel the 10% loss in average fps on a 3900X.