Form objects vs nested attributes in 1 to many association

Recently I have been reading about form objects and have been wondering
its
use in 1 to many assocation.

Let’s say I have a model of project with many tasks and the user edits
the
project along with the tasks in one big form.

Is nested attributes using cocoon gem better suited than using
reform/virtus or other form objects? Any examples of using form objects
in
this context?