We use Skype for Business at work, however when the boss isn't watching we switch to appear.in since it works much better and doesn't require craptastic software.
But, the boss will see when you're "available" straight from Outlook, which is where he lives. It's not an IM tool, it's (yet another) instrument of workforce control.
Also, despite the rigid security policy where I work, the mac client stores my password in the keychain.