I can’t comment on Teams vs Slack, or on its other productivity features but I’ve been using Teams on a daily basis for some fairly large meetings and it’s never faltered - way more reliable than Skype was at least.
My issue is more with how information is presented and data is stored. I think Teams just has too many ways to do things and obfuscates too much at times... finding old docs or old conversations can be tedious and sending messages to wrong "teams" mistakingly is an easy thing to do.
I can't even go fullscreen in a Teams meeting anymore after a "recent" (read: months and months ago) update. My small laptop has 1/4 of the screen taken by UI and taskbar, even in "focus" mode.
