supertab plugin. Now I've settled in the middle, and am loving mediocre vim. The combination is:
Ctags is a beautifully ugly system, with extreme performance and simplicity. Just enough intelligence to pluck out the exports and declarations in your files to make jump to definition work mostly. It's basically a set of regular expressions that tries to find keywords and then puts them in a file that your editor can use as an index.
brew install ctags-exuberant