I have honestly tried Eclipse and Netbeans for my programming, but the learning curve is just way too high. When I started using Emacs, I could do what I wanted almost instantly (open a text file and start editing it). To just open a file in Eclipse, edit it and compile it seems impossible. You need to get the correct plugins for the filetype you have chosen (and I am using many types of files). Then, you need to create a project, figure out what workspace this is supposed to be in. I suppose if I didn't already have tons of projects organised into a nice directory structure -- if Eclipse was my first experience with programming and I could just create new projects in the default workspace -- it would be a little easier, but the existing code adds a bit of inertia to my development style.
I posted a question that got
some airtime on Slashdot about IDE support for multi-language projects. The studio-style apps seem to be built around the idea that you will be using a single language for the whole project. This is not bad as far as it goes, but your existing codebase is Python, C, C++ and Fortran with lots of shell scripting, m4, awk, sed and Makefiles in between, the studio stule stuff doesn't cut it. Not to mention, that even when I'm working on a large project in one language (which Ecipse does well), I may want to open a text file of some other kind (XML, CSV, whatever) and Eclipse doesn't make it easy in the same way that emacs does. I also can't fire up Eclipse from the terminal to edit a file from home via ssh. And I haven't found a text editor that does indenting the way I have grown to love -- by hitting tab anywhere and having the indentation done right.
Now, I know all the arguments for IDEs, and I have really tried, but I think many people are like me in using Emacs because they are (or at least feel) more productive in it on their codebase. The underlying mindsets are just so different that it's really hard to get going in IDEs.