+1 on what christofferbengt and logicwave said.
We need to have items on the planner board that are assigned to a particular user added directly into that users' personal calendar and NOT a separate calendar. To put it another way, we need users to see the tasks assigned to them alongside their own meetings and their own schedule, not require them to open another calendar to see tasks.
It will be OK to have the tasks set as "all day" on the due date set in Planner (so they appear at the top of the personal calendar and do not block time). Ideally, I'd also like to be able to set alerts from within Planner too, but can live without any alert, as long as the task shows on the users' personal calendar and NOT a separate calendar.