I have been a vim user for a long time, but I'm also lumping in various varieties of 'vi' in with that. For most of the time I have used vim, but there were times where I used nvi or elvis or the vi that came with some variant of a commercial Unix operating systems. But why?
Mostly because it was the first editor someone showed me how to use and then it just sort of went from there. I maintain that the vi vs. emacs argument is flawed because both programs require training yourself over a long period of time. There is nothing inherently intuitive about either of them.
I'm going to say that I've been a vim user for 20 years. I started using it before that, but those years were a mix of nvi, elvis, and vim. And I'm going to subtract some years from that because I didn't make effective use of my .vimrc until later.
I have never given Emacs a real shot. Mostly because I didn't want to invest all the time in to learning another program that was still going to leave me with just another editor. And for a long time I didn't care. But recently I have found myself wanting more out of my development environment. I have tried many vimscript plugins and external tools and they are nice, but I still have about a zillion vim sessions open and it never quite feels well integrated. Internet tells me that people have nice Emacs setups for development, so maybe I should try that.
OK, I'll do it.
About a month ago I looked in to doing this and then about 3 weeks ago I decided to make it happen for real. On my workstation at the office. I installed emacs and removed vim. When I type 'vim' now, I get command not found. I forced myself to use emacs as-is without modifying the configuration file for the first week. I made notes on paper and focused on the basic commands and training myself out of vim muscle memory.
I have also been writing up blog posts to post later as I have moved over to Emacs. I am still using it and I like it. I will post my Emacs entries later, but for now I will post a link to my now growing .emacs file.