-If you have a 4k monitor take the 295X2 and buy a PSU 200 watts bigger than you have now.
-If you have a 1440p monitor, and use the cards "outta the box" with no overclocking via Afterburner, get the 295x2 and buy a PSU 200 watts bigger than you have now.
-If you have a 1440p monitor, and overclocking via Afterburner, keep the 970s
-If you have a 1080p monitor, keep the 970s
The above assumes PhysX, G-Sync, Shadowplay, heat have no bearing on the purchase.