I use Planner at my work. However, the big drawback of it is that it is not designed to support holistic project management which includes project Logs, Documents repository and/or adding links to documents. I still try to use it beyond the "task only" functionality and use individual "task" in the bucket as the project with links to OneDrive docs (Word, Excel). However, the problem is that only 8 links can be used per task and they cannot be further organized. Planner is task & timeline focused which are not the only important aspects of projects. It this respect it is limited to planning (like the name of app suggest) but it would offer so much more with a more holistic approach that would prevent to use multiple apps in a project.