I work in a marketing team are have been using Microsoft Teams for a month or so now.
It is a really good tool allowing us to share resources and conversations etc across quite a large number of multiple projects. Planner is good at managing tasks. The big downside we see is that plans created for channels in a team are not visible within the Planner hub, so we can't get an overview across all projects.
Before planner we were creating a new group for each project but that was getting unwieldly as we have eight to ten new projects per week.
Teams solved this as we now only add a channel for each project (perfect :)) except for the inability to use the planner hub for complete oversite by project or project group in the planner hub.