This is the real comment here. I've worked in all three, scrum, kanban and waterfall, and I know from personal experience that they all have their shortcomings and it really depends on what you are trying to deliver and how well your team responds. We've moved from waterfall to scrum to kanban and back and the one standout is clarity of minimum requirements and boy is that hard to get from the relevant people. If you don't get that then stick with waterfall because then no one is responsible!