Auto-promotion here :-D Check Spacemacs, it is an Emacs configuration usable by Vim users out of the box. It has the feature you mentioned powered by the which-key package.
I'm a spacemacs convert after using vim for 2 years. This editor + configuration is extremely hard to beat. I just pulled from master after using it full time for two months and updates were amazing.
Way better ergonomics than vim and elisp is extremely easy to hack on.
As a counterpoint - I went back to VIM after a month of spacemacs. I've actually put in the effort to learn the keybindings for all the relevant tasks I needed and the way Emacs works internally, as much as it's possible in a month.
I was doing Clojure and the main problem for me was the less fluent editing - most commands in vim are at least one keystroke shorter. The other big problem are non-evilified plugins that completely mess up the workflow - you constantly keep switching between "I'm in VIM" and "I'm in Emacs" mindset. Also, emacs feels a bit more sluggish, although that may be just CIDER.
The things I loved:
* helm mode - autocompletions for the commands
* consistency - SPC + ... everywhere
* REPL in a buffer
I understand that a month with Emacs isn't remotely enough to make up for years of VIM, but I didn't find enough benefits to stick with it.
