I started off using Emacs a lot (like tons and tons of Emacs with tons and tons of custom modes, functions, and craziness - network pong anybody?). For almost a summer, my xinitrc at the school labs literally opeed up a full screen Emacs; it was my window manager too.
The simplicity of vim (and pretty colors) drew me in. Plus as I learned more sed/ed, I understood vi more. That, and a slow connection from off campus really sucks. I learned that too pretty well. Well enough to hack together some vim scripts, but nothing near my Emacs level. I feel like vim mode hacking is a beast you need to be specially equipped to handle (and I can write APL in any language so it isn't the syntax).
Then Eclipse and IntelliJ came around and I only really used vim for quick one off stuff (if I didn't use printf, echo, or cat). The only time I used vim was for C/C++ or something esoteric, like KDB+/Q/K, that didn't have their own dev environment (unlike say VHDL or Matlab where I could sit in their ugly cocoons).
Now I'm growing tired of the very buggy, slow Java environments that seem to require a gaming rig to compile HelloWorld.java (or sorry, HelloWorld.xml with SpringBoot). And I see all these poor Emacs clones playing catchup with 2000. You have editors written in JavaScript inside a web browser with modules transpiled to JavaScript (for some reason JavaScript is too low-level to write text editing packages in now -- God help us all). That, and they don't support a tenth (I'm being generous) of the functionality that Emacs does and they probably never will.
What is so hard about an extensible text editor? Just getting the basic hooks down for self-insert and movement without having to go to swap?
I remember when Emacs was called "Eight Megabytes and Constantly Swapping". I now see Atom routinely take up over 800 MB. And it still can't play Pong.
Now with Rust and other languages, I'm back home in Emacs, but the keystrokes do tend to bother me a little. I liked the HJKL movement keys in vim - I just hated the modality and think I spent more time trying to figure out "my cursor is here, but I need move it over there - so first I need to jump on that log, shoot the rocket to knock down flowerpot then run quickly while the line is falling to catch it and K it to the next line" -- like some sort of weird text editing puzzle (I wonder if you could make a vim code golf puzzle set).
Emacs has these bindings that feel like finger yoga, even when I've remapped Caps, control, half my F-keys, etc. What I really need to do is remap my toes to my hands, I think.
It would have been really nice to see C-[hjkl] style movement (with maybe CS-[HJKL] be the distance mods or something). It's too late now. You of course you can remap those keys, but too much of that behavior is baked in to people).
Maybe one day when I'm old and gray I'll do the Knuth thing and start a new text editor, but before that I'll probably need to redo the monitor, mouse, and keyboard and that is just too much right now.