The obvious example would be using the neo-vim frontend to interact with VSCode, Eclipse, IntelliJ, etc.
What I want most is a Neo-Vim frontend to org-mode in Emacs, because it would be hilarious and because while Spacemacs is kind of cool it's still not Vim. And org-mode is awesome and unparalleled but vim > emacs all day.
Another interesting approach is VimR (http://vimr.org/), which is Neovim combined with native IDE addons such as Markdown preview, file tree, etc. The nice thing about VimR is since the whole thing is one cohesive package, the developers can ensure it has a consistent experience. Sadly it's OSX only though.
From the prompt, it is faster to open a large file in vim than emacs since you have to wait for all of the spacemacs plugins to load.
M-x customize
The problem is vim editing never quite mixes well with other editors. The vim plugin for VS Code is great, but do you let it take over Ctrl? Do you get Ctrl-R for redo, and sacrifice other VS Code usages of Ctrl for example? The vim plugin is also pretty buggy here and there and no matter what, I always find a vim plugin is missing some vim feature I depend on.
It's frustrating in a first world sense. It's hard to have your cake and eat it too with vim.