I was partial to Asus thru the 6xx series ,,, MSI and Asus were kinda even with 7xx and since then, to my eyes, MSI has ruled the day, at least till I see something that says different. If ya look at the componentry, MSI has the edge. Unfortunately, with the 10xx series, Boost 3.0 kinda gets in the way which makes it difficult for manufacturers to distinguish themselves from one other.
If you have $10 extra to spend and are water cooling with something like the Swiftech H240-X2 cooling ya CPU, then the Seahawk with pre-installed EK full cover water block is a superb choice. Add water cooled GFX card to your rig in a few minutes.
I have yet to see a good tear down article comparing the componentry of the 1070 series but MSI took the crown with a far more robust build with the 970.
http://www.bit-tech.net/hardware/graphics/2014/09/19/nvidia-geforce-gtx-970-review/2
More phases on VRM, better cooling features (fans independently controlled) , better VRM and memory cooling and hardier components