Selection of Regulator type (Module(Integrated Inductor) vs converter(Internal Switch) vs controller(External Switch))

Hi

I am trying to design a +15V, 4A supply from 24V source. What are the criteria for selecting type of regulator I.C? Should it be a Module or a Converter with internal switch or Controller with external switch?

What are the advantages or disadvantages of selecting one over the other?

Thank you

Sai Krishna