It took me 2 weeks to switch to vim. Now I rarely use the vim itself, but I use vim plugins in all IDEs. To be honest, I don't like vim's plugin infrastructure, scripting language and a lot of other things, but the core - composable single-key commands - is a gem.
Emacs I gave a try for a month, and I still felt like a beginner. There isn't a single core idea that you can master; it feels like it's a never ending series of chords that you have to remember for every plugin and lisp code that you have to write to configure and personalize everything for yourself. And pre-configured distributions like Spacemacs feel even more complex. Evil mode behaves like vim 95% of the time, but 5% leaves you buffled and completely, utterly lost.
Sometime in the future, when I have enough time on my hands, I will build myself an emacs build from scratch, learning every plugin as I go along. Right after I build my own linux distribution from scratch - oh wait, I already did that, and it took less time and mental space than Emacs.