Improve Sign Up/Sign Experience for New External Users
I had a bad Teams day trying to get external users into Teams from a client project team.
In terms of competitors, I think Basecamp is a good, clear and reliable user experience: 1) invite the user via email, 2) they verify and 3) they sign in. The email doesn't matter.
The Teams external user experience is very far removed - please make it a simpler and better experience - it is after all usually the first experience a new user has of Teams.
I always advocate either SharePoint of Teams on the projects I work on - but the external user experience is really not fit for purpose any more compared to alternatives.