I have done a lot of insulation jobs and rigid insulation is really the way to go for almost any project. Roof insulation is so much easier and so much more effective when you use rigid insulation.
Rigid foam insulation is also the best option when you are installing insulation behind drywall. If you are working with experienced contractors the job can go incredibly quickly. You have to know about the various kinds of insulation types and make sure you are using the best material for the job, but once this decision has been made there is not a lot left to do.