~20 years ago I became an early IntelliJ user. From version 3 maybe? It's hard to recall. I've never looked back.
But I did try Eclipse and... I never got the appeal. For one, the whole "perspectives" thing never gelled with me. I don't want my UI completely changing because now I'm debugging. This is really part of a larger discussion about modal editors (eg vim vs emacs). A lot of people, myself included, do not like modal editors.
But the big issue for Eclipse always was plugins. The term "plugin hell" has been associated with Eclipse for as long as I can recall. Even back in the Subversion days I seem to recall there were 2 major plugins (Subclipse? and another?) that did this and neither was "complete" or fully working.
To me, IntelliJ was just substantially better from day one and I never had to mess around with plugins. I don't like debugging and maintaining my editor, which is a big reason why I never got big into vim or eclipse. I feel like some people enjoy this tinkering and completely underestimate how much time they spend on this.