The s7 is a better buy.
The s6 uses a 64-bit SiP chip dual-core processor, while the s7 is equipped with a dual-core S7 chip, and the performance is twice that of the s6.
The display is different, and the s7 has a better watch color display, allowing users to see the screen even in sunlight.
Different shell materials, s6 shell materials are aluminum, stainless steel and titanium. The s7 housing is made of aluminum metal.