I started using emacs in the early 90s and got really into it during uni, studying CS a couple of years later. In mid 2000s I ended up in sysadmin work in a mixed Unix-environment (Tru64, AIX, Solaris, Linux) in a group where all other used (some Vi(m)-variant). I tried to get work done with emacs but failed due to various special characters always getting mangled in different ways over different terminals on different platforms and after a couple of months I gave in and started using Vim instead. I finally understood that Vim had two essential properties that other editors lacked in this case.

1) It works well in environments where special characters will get mangled in various ways over different platforms. As long as ESC works, vim will do the work just fine. 2) The modes makes it very reliable to use when you have to make specific operations in exact places in text-files. This alone should make it the goto editor for sysadmins where you often have to make just a few character changes to a configuration file and be sure you do not change anything else.

A third reason when starting the work was also that Vim came by default on all out platforms so we knew it existed there and it was a nightmare trying to get approval for extra packages to be installed, but the first two reasons are what keeps me coming back to Vim whenever I need to do some text-file surgery.