I work on a large C++ codebase in emacs. I find emacs keybindings and extensibility (via elisp) far superior to any IDE - and I have tried Eclipse, CLion (IDEA for C++), Code/Blocks and Netbeans.

For C/C++ specifically, the state of code analysis in emacs has greatly improved due to clang. For example, I get full auto-complete (including for variables declared 'auto') in emacs with irony-mode [0] for code completion, flycheck-irony [1] for on-the-fly syntax checking, and I get jump to definition/find references/etc via clang-ctags [2]. I assume vim has similar extensions.

[0] - https://github.com/Sarcasm/irony-mode

[1] - https://github.com/Sarcasm/flycheck-irony

[2] - https://github.com/drothlis/clang-ctags