Another question is how your users are connected to the network. Does your application require users to be always connected, mostly not connected, or somewhere in between?
Some applications may require a constant connection to the network in order to function properly. This architecture is sometimes called thin client. Depending on a constant wireless connection can be risky. The technology is still not completely reliable, with long distances or other obstacles that can interrupt an important data transfer.
Will your users collect data in the field on a mobile device and be connected to the network only when they want to download the data to a server? In this situation, a device needs to allow local data storage until it can be "cradle-connected" to the server.
A mobile device can also store data locally for an application that may or may not be connected to the network at any point in time. With this smart client architecture, the application can still function and a user can access data with or without a network connection.