Collaboration depth
monday.com
Assignments of one or more owners, in-task comments with @mentions, shared boards, Gantt charts and dashboards that compile one or more boards are all documented, and workload appears as a named dashboard metric with agents assigning work by capacity and skill set. I found no public information on guest or client access with its own permission model or on explicit dependency management, so shared planning stops short of the full multi-team span.
Stackfield
Team-level planning is first-class: assignments, comments and subtasks on tasks, four dependency types with automatic rescheduling and a critical path, cross-project portfolios from Premium, and a member perspective that shows all members' schedules together. Guest and External roles come with sane permissions — local links never extend existing access — and unlimited externals are free from Premium. We found no public information on a dedicated workload or capacity view, which keeps this below the very top.