Personally, I think g-sync is awesome and I would definitely get a g-sync monitor if I am going with nvidia for the foreseeable future.
Both of these panels are TN panels. They will look and perform the same. But if color is important to you, then you may want to go with an IPS panel. However, IPS panels have a longer lag time (5ms compared to 1ms for TN) and cost a bit more. If you are going to go with a gtx 1070, then I would recommend 1440p.
Here is a 1440p TN panel with g-sync that will look very nice. It's color may not match that of a IPS, but it will look fantastic and pair very well with a 1070.
https://www.newegg.com/Product/Product.aspx?Item=N82E16824011057