The new iPhones look exactly like their predecessors, with the rounded, unibody anodized aluminum chassis available in silver, gold, and space gray.
The iPhone 6s has a 4.7-inch 1334 x 750 pixels display at a pixel density of 326 ppi while the iPhone 6s Plus has a 5.5-inch 1920 x 1080 pixels display at a pixel density of 401 ppi. You’ll be able to see more content on both phones, but the iPhone 6s Plus has an ever sharper display, which means text would be crisper, and the 1080p resolution will be great for watching HD videos.
By virtue of being larger, the iPhone 6s Plus also has a longer battery life. The iPhone 6s Plus rear-camera also has Optical Image Stabilization, which makes it much better for low-light photography. It now works with both photos and videos (in case of the iPhone 6 Plus it only worked with photos).
The folks at iPhoneHacks made a nice table comparison between both devices from everything..
Quick summary of the differences
- iPhone 6s Plus comes with a bigger and sharper 5.5-inch Retina HD Display.
- 12-megapixel rear-facing iSight camera has Optical Image Stabalization (OIS)
- Better battery life.
- iPhone 6s Plus is slightly heavier than iPhone 6s.
