The larger the sensor the more light the sensor captures yielding in better image quality.
23.6 x 15.8mm
Polaroid Snap: 81.2 x 25.4mm
3. focus points
The more focus points the more flexibility in picking which part of the scene to focus on. They also give the image sensor a better probability in identifying the right area of the scene to focus on in more automatic modes.
Sony Alpha a9: 693
4. continuous shooting at high resolution
Fast continuous shooting is useful for catching action shots.
Olympus OM-D E-M1 Mark II: 60fps
The maximum ISO at which the device still captures excellent quality images. Source: DxOMark.
Sony Alpha 7S: 3702ISO
6. has a flip-out screen
Flip-out screens are useful for doing tricky shots.
Optical image stabilization uses gyroscopic sensors to detect the vibrations of the camera. The lens adjusts the optical path accordingly, ensuring that any type of motion blur is corrected before the sensor captures the image.