rcald2000 :
While either monitor will basically work with your GTX 970, the adaptive feature will only work on a g-sync display with a Nvidia graphics card.
Here is a question I pose, and I admit that I don't know the answer to: Does g-sync offer any benefit if your current graphics card doesn't produce FPS above your displays maximum Hz spec? I currently own a g-sync display and I previously owned a GTX 970. That card is ideal for 1080p @ 60 FPS, but in most games it won't produce frames too far above that. I just wonder if a g-sync display is the best use of your upgrade dollars, unless you simply want it because you want it. I could certainly understand that mindset.
I've always had my 970s SLId together but I can tell you that when I did some OCing I managed to pull well over 200+ in some games like Diablo 3 and at the lowest 100+
From what I've read Free Sync will do what Gsync does at a lower cost and I've read that Gsync forces Vsync to be on where as Free Sync does not. Also, Gsync takes away your monitors settings ability I believe.
http://wccftech.com/amd-freesync-nvidia-gsync-verdict/
BUT
alternatively I read this article which leans heavily towards Gsync
https://www.rockpapershotgun.com/2015/04/09/g-sync-or-freesync-amd-nvidia/
It's hard to tell who is biased and who's doing the research