Sound Branch is described as 'VoiceFirst team communication app that lets you communicate with friends, colleagues and beyond with voice messages. Talk and listen to the people that matter in your world and grow your own voice in a place where we can all be heard' and is an app in the Social & Communications category. There are more than 10 alternatives to Sound Branch for a variety of platforms, including iPhone, Android, Windows, Mac and Online / Web-based. The best alternative is Wire. It's not free, so if you're looking for a free alternative, you could try Mumble or TeamSpeak. Other great apps like Sound Branch are Zello (Free Personal), Sesame Chat (Free Personal), Voxer (Freemium) and Ventrilo (Free).
HeyTell is an "Instant Voice Messaging" system that allows users to connect in a manner similar to a push-to-talk radio handset. It supports different privacy levels as well as a friends list and geolocation.