IMO, methodologies are mostly just theatre to cater to stakeholders and their preferences and fears, and are otherwise BS from a development perspective. And in my experience, regardless of what methodology you use, what happens in practice (in the grand scheme of things) largely ends up being the same anyhow. Rather, the speed and success of a project seems to have nothing to do with the methodology, and everything to do with the particular project, people, constraints, and requirements.