I don't use MSFT teams, but I've seen a demo and it looks far superior to Slack. I imagine they'll be using some of those funds to shore up feature parity with MSFT.
I wouldn't be too worried about Google. Hangouts and Chat are by far the worst products I've ever used. I can't think of a single piece of software I loathe more than Hangouts.
They're supposed to be significantly improving them both - we'll see. I think it would be hard for them to justify spending something like $10b for Slack when it doesn't help move the needle on competing with Facebook.
I wouldn't be too worried about Google. Hangouts and Chat are by far the worst products I've ever used. I can't think of a single piece of software I loathe more than Hangouts.