It's great that you achieved a minimum of 60 fps with your 970. I sure can't run the game at 1440p and 60-87fps with no dips below 60fps with mine unless I downgrade the graphics to a point it doesn't look nearly as pretty as I would have liked. I think aliasing and pop in can make a massive difference in a game like GTAV. I honestly think it's the best looking game ever with everything maxed and smooth IQ.
Though personally I haven't locked to 30. I tried but I think unlocked 30-40 feels better to me.
That's the wonderful thing about PC gaming: options.
Most people who own a PS4 or XONE have. I don't have a next gen console though, and 6 months ago the game didn't look this good.