I started with IDE and then moved to vim. Not because it's "cool". It's productive. There are several reasons. First off, movements. Almost any IDE now has some plugin to imitate vim-style keyboard shortcuts, but they honestly suck at it. Next thing is it's fast and lightweight, which surprisingly feels more important than I thought before. I don't have to wait for java-based IDE's GC to stop running or something. Third reason is that I can set any action to any key, I can invoke anything from the vim itself to automate some text-processing, make any visualisations I need, anything. IDEs also provide some mechanism for that but it's way more complicated and obscure. But the key reason is simpicity, really. I know what happens underneath the hood, because I manually enabled the plugins I want, I've set shortcuts. Vim serves me, not otherwise. Back when I used to write programs in Java I tried Idea and switched to Netbeans, because Idea is way too "smart". It tries to do everything automatically, which is OK until it fails. And it did fail sometimes. But when it fails it's me who has to find what did it mess up. So I prefer to write code myself (or let do it some scripts I explicitly authorized to do so), not to fix something my IDE broke. It is especially uncomfortable on some old messy projects with lots of legacy code.

Is vim perfect? Well, for me it's not. Because of vimscript, because it doesn't have mechanism to work with non-text information (for example it has to open up another window to show me rendered LaTeX). Sometimes I even think of switching to emacs. Plugins to do some advanced processing (like rope for python) are slow quite often. But I still prefer it to any IDE in most cases. It's not perfect, but it's the best thing I've met so far in this imperfect world.