I haven't seen any really good DX12 implementations personally - they generally seem to have issues like stutter or have a bloated "feel" and struggle to feel like 60 FPS until you are way over that, etc.
Exactly. We've had this DX12 argument for YEARs now. The truth is by the time DX12 is relative and DX11 is legacy, there will be new gpus from both vendors out. I wouldn't factor that into a purchase.