We've been setting it up to use with our team. And group chat works great. Except: you can't mute a group chat. You can't mute any single conversation; notifications are all or nothing. Meaning, when you have a big project, your phone is "always buzz" or "never buzz." Meaning it's now useless to me as an SMS type system where I want to know when a single person messages me.
Argh. We are thinking of switching to Whats App. Don't ever let anyone tell you usability is not part of security.