Photo courtesy: Apple
Although I'm perfectly fine with my 18-month-old iPhone 6 Plus, I'm recommending the "new" iPhone SE to some of my friends who have an iPhone 5s.
It's basically an iPhone 6s tucked into a 5s minus 3D Touch. In addition to a beefier processor and a much-improved camera, the SE comes with Apple Pay functionality, Live Photos support and a much faster Touch ID experience.