iPhone 6 had a killer feature some had been waiting 5+ years for, its size. The 6s has... 3D Touch and bit better camera.
And twice the RAM (1 GB iPhone 6 vs. 2 GB iPhone 6s) and a faster CPU and other goodies.
And twice the RAM (1 GB iPhone 6 vs. 2 GB iPhone 6s) and a faster CPU and other goodies.
I bought a 6s and love it (since I upgraded from a 5) but if I already had a 6 I wouldn't have upgraded.