One thing I get asked a lot about by junior developers I bring into teams is what editor they need to use. In some companies everyone uses an IDE, in others you get to choose your own editors. Over the past 30 years I've worked with almost every editor on the market. When I was a Contributing Editor for Computer Language Magazine, I'd do a yearly editor review and test every editor on the market. Since then, I've used dozens (starting with "ed", "vi", and "Emacs") and always seem to narrow down to a very select few, always for the same reasons. But my favorites can wait a few minutes.
A source code editor is a vital tool for any developer. It's very rare to find a developer who uses a word processing program for development (although they do exist!). Most developers these days use integrated tools. The trend in the last two decades to all-in-one editor/compiler/debugger tools (such as the Visual Studio suite from Microsoft, for example) means that most developers work with these editors as a matter of course. Built-in editors are a mixed bag. Some are good, some are bad. The advantages of integration are clear (automatic go-to, launching compilation and execution, etc) and there's also some bad points (you gotta like their editor or else!).
But then there's the old developers like me. I never really liked integrated editors because they don't the speed or capabilities I've wanted. Some have been pretty good, some even very good, but none have been as good as a standalone editor for me. Back in the days when I was a very active developer (before Windows!), WordStar was the quintessential text editor and it was fast and simple to use (once you mastered the obtuse Ctrl sequences, that is). Generations of developers grew up on vi and Emacs, neither of which was friendly, but they were blindingly fast to use.
So you end up with a mixed bag. Some developers will stay with the integrated editors, and some, like me, will always use their external favorite editor. For the last six years or so I've used UltraEdit, and never regretted it for one day (try the eval: you might like it!). Your favorite editor is your choice, but editors are productivity tools and need to be chosen carefully to get the most efficiency out of your coding.