node-vim-debugger https://github.com/sidorares/node-vim-debugger
presentation: http://andreysidorov.com/presentations/melbjs/0913/
I tried this for Python and was greatly put off by the need to download an obscure debugger tarball from ActiveState with some weird license on it, then (according to the vdebug documentation) run a very long command line by hand passing the name of the script every time I want to debug something.
If I am going to trouble myself with that, it's hard to understand why I don't just run a standard standalone debugger which works in the expected way, from the command line. I definitely don't see how it reproduces the experience of (say) pressing a debug button in Visual Studio or Xcode.
Still, if you're trapped in the DBGP world for whatever reason, vdebug is miles better than any competition that I've found.