Teams is unique in how it "ticks all the boxes" but has enough small flaws and unfinished implementations that it makes for a really, really awful tool. There are fundamental problems with the software. To name a few:
- The notifications are wildly inconsistent - sometimes I'll get 5-6 email notifications for a single message that I already saw, sometimes I'll get email + app notifications for messages I am currently viewing, sometimes I'll get no notifications via email or app, for stuff that happened when I was offline.
- The way every message is like a new "post" and there can be replies - this is a unique idea, but just really bad to use in practice. When people reply to a post, it gets bumped to the bottom, so posts end up out of order. Also, all the replies to the post automatically get collapsed, making it really annoying to find anything.
- The mac app decided to stop displaying new messages (for WEEKS) in certain channels including our service errors channel - I finally gave up and can only use it on the web.
- the O365 file integration regularly crashes the browser and mac app. We share a lot of spreadsheets and this just sucks. Sharepoint sync on the mac breaks all the time. It spins and fails to track updates.
- O365 collaboration in the browser is brittle, especially disappointing compared to where Google Docs was 5+ year ago.
- The Teams search cannot find documents by name.
- The messages seem to be backed by email files in sharepoint, which makes a mess in sharepoint (not that it isn't kinda a mess already).
After using the google suite at many companies for many years, and having the standard on-prem microsoft stuff, I have to say Teams is not a viable solution for a software team. Teams "ticks all the boxes" but the execution can't compare to Slack.