As far as casing and appearance go, the iPhone 6 & 6s appear very similar. The “S” logo on the back of the iPhone 6s is the mark that lets you know which model you have. But aside from that, it can be a bit tricky to tell the difference between the two devices. However, in terms of performance the 6s was a significant update.
The upgrades include, 3D touch, a better camera, live photos, faster processor and more RAM. The 6s also introduced the rose gold color option. 3D touch on the 6s means that you can navigate differently since this model can distinguish between a hard press, a light press and a tap. Video recording on the iPhone 6 is in 1080p and the iPhone 6s made the jump to 4k.
In terms of battery life the original capacity on a new phone was estimated to be approximately the same on both of the models at 10hrs of internet browsing or 11 hours of video playback.