I have a GTX 760 and Radeon 290X in my machine. The Radeon is twice as good. 290X is on par with 480/580. Same score in Superposition, 2500 points on 1080p Ultra.
GTX 760 is usable for games that were released approx. 3 years ago.
Like Assetto Corsa, Elder Scrolls Online.
I wouldn't buy a GTX 760 today. I replaced GTX 760 with the 290x 2+ years ago, that should tell you something.