Scrum, Kanban, &c. is a complete irrelevance. Most of these processes—and some are useful—are orthogonal to agility. When a process is imposed or you feel obligated to "follow the rules," they’re much worse, of course, moving you in exactly the wrong direction. Allen Holub on Twitter
This seems to be something that few understand about being agile. Processes like scrum can be useful, as long as there is a very acute awareness of how they can be used to maintain rigid waterfall like processes. A few days ago, Allen commented that Scrum is "mostly harmless". I couldn't agree more! But when used as a process to transform a command and control/waterfall organization, it's very harmful, because it makes people continue to feel like rigid processes work, when it doesn't. i.e. It brings a false sense of agility, while maintaining their waterfall heavy process mindset. At the end of the day, Scrum is mostly harmless in the hands of those who understand real agility; but it's also not really beneficial.
Because of Scrum's implicit rigid nature, it's not a great process to use for transforming an organization from waterfall to agile. Some argue that waterfall organizations can't be transformed to agile ones at all. They claim this is mainly because many of the managers in those organizations see agile as a threat, so they end up faking agile and maintaining their illusion of control, at the detriment of the organization. I think this is a bit of a pessimistic view myself. However, if managers can't let go of their command and control heavy process mindset, where they make all the core decisions, as opposed to the team making the decisions, that organization can't be agile. They'll end up doing the same old heavy process, with all the inefficiencies that go along with it. This is because it's those on the floor who know what the bottlenecks are, and how to fix them.