One of these days, I'm going to sit down and try out this, emacs-evil, and neovim. Side-by-side. Need to figure out which one I like most.
There's a lot more polish in the integrations for emacs than vim, likely as a result of literally everything in the editor being a function call that can be hooked into.
The only thing I miss is solid tab functionality (there's a short of hack I've seen so far, but feels too rough for me). But honestly, with projectile + heap, I barely miss that.
Company-mode far outpaces the auto completion options in vim (though to be fair to the plugin authors, apparently they need to resort to major hacks to perform some of the things they do). Just as an example, when you autocomplete a function call, it populates the arguments and let's you tab through completing them. This same functionality sits as open tickets in the major vim autocomplete plugins, with a response of essentially "this is really hard to do in vim, hopefully we can figure something out in neovim".
It's worth the 2-3 days to make the switch and set yourself up. Also, a recommendation -- autostart emacs in server mode and use enacsclient to connect to that for all your editing needs.
Like you, I loved my vim tabs. But "state" is what changed my mind.
In a few keystrokes, sure I could switch tabs. Right, right, right, right, there that's the tab I want. But it's coupled to my project state: if I close a tab, there goes the muscle memory for that session. Now it's "right-right" to get to the thing I need instead of "right-right-right".
Buffers are invariant to your session state. In a few keystrokes, I could just search for the buffer by the first few letters of its filename.
I routinely keep >500 buffers open in emacs. Ten projects, half a year of journal entries, a few dozen mail messages. Having all those things available in the same number of keystrokes no matter where I am is immensely helpful.
It's like Huffman coding for your workspace.
IIUC it works okay-ish in at least two of them: https://github.com/Rip-Rip/clang_complete and YCM after https://github.com/Valloric/YouCompleteMe/issues/36.
(Happy Emacs user and contributor here; just want all editors to stand on their merits).
On a side note, one of those days I'll just have to drop everything for 2 weeks and just learn Emacs.