Visual Studio, or Eclipse have been around for a fair while as well now. Its not like they will disappear with the next text cycle. And you can get productive with them in far less than a year.
For example, I gave Visual Studio another shot recently (VS2013); and I mean, I read books on using it productively, I read the various tip blogs, advice for customization online, et cetera; I used it extensively. Unfortunately, I just don't see what people see in it. From my point of view, it's still slow, cumbersome, expensive (for any version with features that are actually useful), much less featureful than (customized) emacs, and doesn't run on most of the platforms I use to develop software. In theory, I could dedicate a few years writing extensions for one of these IDEs to duplicate all the emacs modes I use, but I'd probably never be able to fix, for example, buffer switching, or all the places where the mouse is the preferred form of interaction, or where modal dialogs steal focus (let alone all the dialogs that inexplicably aren't resizable). Meanwhile, the nice features like Intellisense and so on are the kind of customizations I've had in emacs for most of my prefered languages for years anyway.
The difference is: the flexibility of IDEs stops after a while, and then there's nothing new to learn to become more efficient. With Emacs, you can keep on learning and optimizing your work environment.
Disclaimer: I work with Eclipse almost exclusively these days, also because for Java it's so much better, IMHO.