This should have been a comment, but it wasn't fitting in a comment length, so I posted it as an answer.
All the benefits mentioned in other answers are achievable by simpler means than using maven. If, for-example, you are new to a project, you'll anyway spend more time creating project architecture, joining components, coding than downloading jars and copying them to lib folder. If you are experienced in your domain, then you already know how to start off the project with what libraries. I don't see any benefit of using maven, especially when it poses a lot of problems while automatically doing the "dependency management".
I only have intermediate level knowledge of maven, but I tell you, I have done large projects(like ERPs) without using maven.