Plus ctags isn't really that smart, or you can say the way it is used. For example I have a struct "foo" that has different independent declarations in several files in my source tree. Whenever, I would try to open that tag, list of all tags would show up regardless the files included in the current source files. This is quite irritating.

Another not-so-smart feature is auto completion (in C++ at least) and refactoring.

However I can live with these missing features as once you get used to something like Vim or Emacs, its quite frustrating to work on bloated IDE's.