I went from a 290x to a 780ti to a 290 and now a 780. Without tools they all seem about the same to me at 1440p. The 780's feel a bit more polished and premium compared to the AMD cards. I never found mantle to be anything special tbh it was always smoother using DX on BF4 for me.
If you have always had AMD go Nvidia and see what you think. You can always return under DSR if you get scared.
If you have always had AMD go Nvidia and see what you think. You can always return under DSR if you get scared.