What's interesting is I just re-tested with my new card, I got a used EVGA 1060 6GB SC very cheap, so that's my upgrade. My benchmark scores are up about 20% for Heaven and Valley, but are actually worse for Superposition, so this might be one benchmark that runs better on AMD.
As for my old R9 290X, my brother wants to buy it off me to replace his Radeon HD 6870 crossfire setup, so it's a win/win situation. He's getting an upgrade, I'm getting a slight upgrade but one that's much newer and uses far less power and is much quieter and it's only costing me $100 to change over. Anyway, he's got a 1500w PSU where as my 600w unit can now take it a bit easier and I can overclock my CPU a bit.