The most popular neovim feature (based on reddit's reactions) seems to be job control, although not enough people are using it. You can start an asynchronous job via `jobstart('name', 'prog', ['arg'...])` which will return a job id. You can send data to the job via `jobsend(id, 'text'). Every time the program has some output available, it will trigger an autocmd to let you process it. (This happens synchronously.)

We have refactored some of the code base using modern coding standards, which makes it more hackable. Some of these systems have become more efficient by, for example, using pipes over temp files.

We accept upstream patches in order to stay on top of vim, so I hope that no one will ever not use neovim because of a feature lacking (aside from a GUI--see below).

neovim creates a socket for each instance that external programs can communicate with, allowing one to write a plugin or extension in any language, providing it has a msgpack implementation. These plugins may eventually control things like the GUIs, spell checkers, syntax analysers, allowing nvim to become more focused, like a micro-kernel.

As of right now, many people have switched without having any real problems.

Nothing yet. It's not ready. Eventually, better plugins and GUIs without losing what makes vim so productive.

My understanding is that Neovim will make it much easier for plugins to execute tasks in parallel and in the background.

I'd use that for running ctags on save without blocking the editor, for example.

A plugin like eclim would benefit greatly from the new multi-process model.