- BBEdit makes all other editors look like Notepad.
It handles gigantic files with ease; most text editors (TextMate especially) slow down to a dead crawl or just crash when presented with a large file.
The regexp and multiple-file Find dialogs beat anything else for usability.
The clippings system works like magic, and has selection, indentation, placeholder, and insertion point tags, it's not just dumb text.
BBEdit is heavily AppleScriptable. Everything can be scripted.
In 9.0, BBEdit has code completion, projects, and a ton of other improvements.
I primarily use it for HTML, CSS, JS, and Python, where it's extremely strong. Some more obscure languages are not as well-supported in it, but for most purposes it's fantastic.
The only devs I know who like TextMate are Ruby fans. I really do not get the appeal, it's marginally better than TextWrangler (BBEdit's free little brother), but if you're spending money, you may as well buy the better tool for a few dollars more.
jEdit does have the virtue of being cross-platform. It's not nearly as good as BBEdit, but it's a competent programmer's editor. If you're ever faced with a Windows or Linux system, it's handy to have one tool you know that works.
Vim is fine if you have to work over ssh and the remote system or your computer can't do X11. I used to love Vim for the ease of editing large files and doing repeated commands. But these days, it's a no-vote for me, with the annoyance of the non-standard search & replace (using (foo) groups instead of (foo), etc.), painfully bad multi-document handling, lack of a project/disk browser view, lack of AppleScript, and bizarre mouse handling in the GVim version.
