Google's Hangouts is at the top of the Android messaging heap, but for business users not tied to a Google account, it's less than ideal. Enter Cisco's Jabber, a messaging app that taps directly into one of the most widely used office messaging platforms. (The client is free, but you need to run Cisco's Jabber server on the back end.) Unfortunately, it's compatible with only a few Galaxy, Nexus, and Xperia devices.
Jabber is flush with features, including instant messaging, voice messaging, and video calling, and it uses an office alias to keep your personal phone number and information private. It also offers one-tap access for creating a WebEx meeting when the WebEx app is installed on your device.