I think that its benefits are overrated. Agile methods work really good in small teams and often in theory, but once the projects and especially the environment in which the project lives, get larger, then it gets really complicated really quickly and the axioms under which the project needs to run start to collapse.
From my experiences there are two things which come to mind:
First, the basic agile idea is a good idea, and many processes, regardless if they call themself simple waterfall or scrum, are working often in a more or less (formal) agile way. And secondly, if you have a good team, then most processes will work, but if you have a bad team composition, no process will help.