I've updated the post and done a few fixes.
But the main conclusion is still the same - the best card for now seems to be RX 470 8Gb 8000 Mhz. It can be heavly overclocked, especially with modded bios - it can do up to 30 Mh/s ETH with around 150W tdp. It costs 240$, same as the RX 480 ref., but it has better cooling, better oc capability, better potentional life time and has no consumtion problems. So, it's my choice.