Earlier quoted context omitted.
Unpopular HN opinion: Teams doesn't suck. It's not as pretty/lovable as Slack, but it has an additional level of organization (each team gets their own set of channels), you can add tabs of related apps/sites to each channel, etc. As far as I could tell having used both simultaneously for a few years, Teams is a complete superset of Slack.
I definitely prefer Slack. Here are a few reasons off the top of my head. 1. Many users have issues where the unmute button is unresponsive. Typically the workaround is to turn off incoming video feeds which isn't exactly ideal. This is a major turnoff. 2. Difficult to stay involved in multiple channels as described by another comment. I find it tedious to find what's happened if I've been away for a while. 3. Slack…
Looks like there's a free [0] version of teams that supports unlimited search, unlimited app integrations and meetings of up to 100 attendees. Compare to free [1] slack that has limitations of 10k searchable messages, 10 app integrations and only 1-1 meetings
[0]: https://www.microsoft.com/en-au/microsoft-365/microsoft-team... [1]: https://slack.com/intl/en-au/pricing