How is the Mattermost 3.0 upgrade going?

Upgrade from 2.2.0 without any hickups.
We have a team for each of our clients and a seperate team for our staff, so the multi team with 1 account is very useful.
The migration was the real pain though, spend about 10-15 min / staff member (about 30 of them) to gather all the invite links for every member.
Only issue we currently have is, if you get a notification in 1 team you get it in all teams (with the desktop app at least), when you read it in 1 team you still have to go read it in every other tab/team to actually get rid of the notification.
It's like the notification itself propagates fine though all tabs but the notification read does not.
Its really annoying to the point where a lot of staff members only log in to other teams when they need to, and that is not progress. It's actually causing some issues with our clients.
But I am hopeful this will be fixed soon. Can't complain to much, if I would go I would have created a patch+PR myself.