@Rob Gr
I'm not aware of Mingle but it definitely looks similar enough that if they beat Trello to market then Mingle can say they were first.
But both are clearly simple Kanban board digital-analogues.
I've worked with physical Kanbans and digital ones (i.e. JIRA, Trello) and I feel like physical ones are sometines most productive (once a group psychology lens is applied) but I've also worked in the reporting field so, yeah, go digital!
But this Planner thing looks dinky AF, without the awesome simplicity of Trello (and apparently Mingle).