For a really hyped-up application like Textmate, whose users are going to be quite vocally clamoring for both their own pet features as well as beta and alpha
This is why open-source editors have made closed-source editors all but extinct. There are just too many things to do for one person, or even one group of people.
For those who want to buy an editor for MS Windows (besides the reliable warhorse UltraEdit), this may be interesting:
http://www.sublimetext.com/
I liked what I saw 18 months ago, in particular the overview pane, but the author seemed to let it ... rest. The website main pages still give that impression, but I just looked and the author is active in the forum and pushing out betas.
This is an outlier, since the Windows stack is so closed in general. I think a large number of VS users use it because they are forced to by their environment choice (or employer).
I tend to think of editors like TextMate, emacs, and vim to be chosen by people who invest some thought into making the decision, rather than by people that are forced to use something for work.
Perhaps it's an outlier in that the language is more closed than most (and that this gives MS a pretty huge advantage over other IDE makers), but VS really is the best environment for developing .NET. That's why people pay for it, not because management forced it on them.
Xcode is doing decently well too... And TextMate or CSSEdit or Coda or Espresso or BBEdit...
The "Open source killed closed source" argument doesn't really apply to Mac OS X. Sure, there's Smultron or MacVim or Aquamacs, but they're not really the most popular of text editors (looking at GUI-based ones).
So what's wrong with jEdit? I've used it on Windows, OSX, and Linux and found it identical in each. It has highly customizable syntax highlighting, and is easy to learn. (Some seem to find the UI ugly, but I don't.)
This is why open-source editors have made closed-source editors all but extinct. There are just too many things to do for one person, or even one group of people.