I have experience working in projects with multiple project leaders and I think there are benefits as well as drawbacks under this approach. From my experience coordination between teams sometimes felt like an issue – some project leaders would debate each other as to what team a particular deliverable/ task is meant to be completed and work that needed to done with the help of a team member from a different team was sometimes tough to coordinate. The benefits to this approach are that project managers are able to tick to their expertise and call upon help from a different team when that expertise is needed.