It has been my pleasure to own and use Tex-Edit and its descendants from ages past through today.
While using Mac OS X 10.6, I was a bit displeased with problems in version 4.9.8 and thoroughly dismayed that it no longer worked in Mac OS X 10.7 Lion. But now:
Tom Bender, the developer, has thankfully put hard work into version 4.9.9 such that it is again my favorite and most used text editor. It is actually a relief to be able to use Tex-Edit Plus X after contending with the multitude of alternatives. It is intuitive, powerful and just works, all without clutter and crud getting in the way.
I write just about everything in Tex-Edit Plus X, then toss the text into a more powerful manager or page layout program for my finished product. I wouldn't do it any other way. When I write I just want to write without any distractions from my text editor.
Then consider the terrific raft of features in Tex-Edit Plus X that reside under the hood. It is THE BEST text-to-speech reader available, bar none. It allows integration of audio, graphic and video into your files. It is the boss of UNIX and DOS formatted text, allowing you to do anything you wish with it. It lets you see an manipulate all your text formatting. It is thoroughly scriptable, including working with Automator. It has a WYSIWYG font list. It allows full font styling, text and page coloring, markup, hilite coloring, justification, indenting, GREP, find and replace, sorting, line numbering, character and word counts, auto-save, automatic character smartening, page numbering, margins, ruler control, soft wrap and RTF (rich text formatting). Did I miss anything?
Get it, love it. There are no 'nags' to buy it. But it's only $15. I own multiple licenses just to thank Tom Bender for keeping it alive, well and excellent.