I'm a current Neovim user who happens to be interested in Emacs. I like Org mode, as well as some other features of Emacs. However, every time I've tried to use evil mode, it's felt crippled. (The Emacs side has been fine, however.) The reason for this, I believe, isn't that Evil is an imperfect vim implementation, but that I would never in a million years want to use stock vim for editing. I use lots of plugins for vim (35 at the moment), and most of them don't have an equivalent in Emacs that works fluidly inside of evil mode. I've tried spacemacs, and it's also not really satisfying. I believe, however, that there is a good solution to this problem:
Neovim, as a project, makes vim better-suited to be used as a component in an IDE. It can be run inside of other programs rather cleanly. Some examples of projects using this functionality are NyaoVim and ONI vim, as well as some projects which use Qt, Electron, etc. I would like to know if anyone has tried to run Neovim within Emacs, or if it's likely to gain some attention soon. It would be wonderful to have Neovim work inside of Emacs so that I could use Emacs as my development environment, then use standalone Neovim for other purposes, all with the same configuration and functionality.
Edit: (not sure if this should be in main post or a comment)
I now use spacemacs (emacs with a configuration that gives it better evil integration and makes it more useful out of the box), and have found that evil suits the vast majority of my needs, and I don't miss vim much if at all. One of the things I miss is the way that keybindings were handled. map, noremap, nmap, nnoremap, inoremap, etc. were all so easy to use and had their own syntax, true to the composable nature of vim's keybindings. However, the modes really are different in emacs. Transient states are great in spacemacs, so is the major/minor mode setup. I would still love to see the neovim team get their editor ("the future of vim") to lower the barrier of entry to arbitrary programs having vim keybindings by simply allowing programs to connect to a neovim backend. That would be great in my opinion. Evil really isn't vim, but it allows you to use most of vim with emacs. However, for now, Spacemacs is great, and offers the strength and ease of configuration of emacs.