Device Selection for Testing

Emulators and Simulators: Use of emulators & Simulators for testing is a cost effective solution but these have their own limitations as all features of app like camera etc cannot be tested on these.
They are also very useful in terms of usability, and especially design, including data input, screen size, button use, etc. 

Cloud Testing Solutions (Remote Real Devices):  The QA team can use the mobile cloud computing environment to deploy and test an application. In the cloud approach, the task and data are kept on the Internet rather than on an individual device, providing on-demand access. By reducing the complexity of the implementation, companies that take advantage of cloud services can significantly reduce project costs and boost the return on investment of a mobile computing solution. 

The big players in cloud testing solution are:
1. DeviceAnyWhere(http://www.deviceanywhere.com)
2. Perfecto Mobile (http://www.perfectomobile.com)
3. Appthwack (https://appthwack.com)

Real Devices:  The QA team should use real device for testing app before release as this is most important since the Mobile application will always be used on mobile devices by end users who may access the application from a remote area with fluctuating network signal strength.
One of the biggest challenge in mobile application testing is selection of mobile devices for testing, the selection of mobile device involves various criteria like OS Version, Display Density, CPU type, memory etc.

When testing enterprise applications, a user survey or device model data from internal systems can be a good source of information to determine the mix of target devices for testing.