A good smartphone, should have the following features;
-- A good battery. If the battery is not good, then you can't enjoy anything about your phone.
-- Connectivity options. What makes a smartphone smart is the various connectivity options which include 3/4G mobile wireless connectivity, Wi-Fi for connecting to the hotspot, GPS for location information, Bluetooth for connecting to other devices.
-- Sensors. A good smartphone should have at least the basic features that help the phone know its surroundings and orientation. An accelerometer is a must but it can help you rotate images and achieve different views on the phone. Light sensor turns off your phone screen when you're making calls close to your ear.
-- Memory: A good smartphone should have enough memory to store your images, videos and apps and enough RAM to run the processes.
-- Operating system. What makes a smartphone smart is the OS. Android, iOS and Windows Phone are the most popular OSes today because they are widely supported.