Application should be tested on emulators or simulators?

On the other hand, emulators/simulators will never disconnect from Appium. They also offer nice options like the ability to choose the orientation or other hardware-related configurations. However, your tests will run much slower (sadly, my tests ran 3 times slower) and do expect some crazy behavior from the Android emulator which sometimes shuts down unexpectedly. Another problem is that emulators tend to allocate a lot of memory.