It's highly appreciated that you guys are fighting the good fight trying to convince Sweepr that the RX480 isn't garbage but it's obvious he has his opinion and its pretty set in stone.
Neutral opinion here, both cards are excellent, this is great for mainstream gamers as they're getting 390x and GTX 980 performance at $250 which is almost half of what it cost last generation.
We have known the DX12 era is going to be one of low level optimizations, every game is going to need them to run at max potential. You can't throw benches from API's that don't suit your agenda in your suite. However I think computerbase's method is one of the better ones as far as keeping the best numbers from each game regardless of API. This is how real people will use games in the real world. If you're on Win 10 and the DX12 path is available with better performance you can bet it's going to be used. Same applies to Vulkan and even more to Win 7 users that get a Vulkan codepath.
Gaming evolved is not Gameworks, both vendors can submit optimized code paths to the game developer. AMD has never locked Nvidia out of being able to optimize for their own hardware. If major game developers start doing shader intrinsic code for GCN it's because they are already doing it for consoles. This is a plus for the RX, but not all gamers are going to be playing DX12 titles this year. Lots of budget users may not even do the Win 10 upgrade and are stuck on Win 7, GTX 1060 makes a lot of sense for these users that are limited to DX11 titles.
TLDR: Both cards are great with AIB coolers, good perf, lower power consumption, and more importantly good pricing. There is always trade off's involved in making a purchase. There is nothing wrong with saying that GTX 1060 is better for ME, but don't make absolute sweeping statements like the RX480 is trash either