I was a hardcore vim user for many years, and switched to Emacs a few years ago.
It’s hard to give a concise, objective reason as to why. My best attempt would be something like “vim is a great editor, but emacs is a great ecosystem”.
I always felt like vimscript got in my way. If I wanted to do something out-of-the-box if was overly difficult to even start. I know there are vimscript wizards out there but it never clicked with me.
Emacs, by contrast, feels like it has no limits. If I can imagine it, I can get emacs to do it. I wasn’t a fan of lisp at first but honestly I have come, over the years, to actually enjoy it.
The thing that really sucked me in though was org-mode. I haven’t found anything like it anywhere else. I use it to manage my team, my projects, my side-hobbies, and my extensive collection of notes. The agenda is amazing and capture templates pull it all together. In the beginning org-mode was what kept the learning curve from driving me away, and now I really can’t imagine using anything else anymore.
Oh, also, tramp is killer. I used to ssh into a sever and open vim there. Every time I was annoyed that my extensive vim config didn’t exist there, but it wasn’t practical to port that sucker over everywhere. Now I just connect from my local machine over tramp. I don’t have to deal with config mismatches, editing happens locally so I don’t have to deal with input lag, and it’s so seamless that I don’t actually miss out on anything. I can edit the file system, open a terminal, run shell commands, whatever.