Apart from the fact that I first had to fix UTF-8 handling in Textpattern and international URLs don't work properly, I'm not really impressed by Textpattern. Sorry. But somehow it seems quite unfinished to me. Sure, it's a CMS and only incidentally designed for blogging - but where is a calendar? Where is time-based navigation? And the available plugins for that don't particularly excite me either.
You can upload images - that's the bare minimum. But file extensions are checked case-sensitively. And as a result, you can't upload images directly from the camera - on OS X they're usually copied with capital letters in the extension. Besides, images are also missing even the most rudimentary handling - creating thumbnails according to specifications, folder management, etc. The fact that there are translations is nice - but why are they only 90% complete? Help is available too - but not for every element. Sure, writing help texts is work. But if you have input fields like "closet" and "cupboard" in the advanced options of a post, you shouldn't be surprised by user questions. There's almost no documentation - at least none that I could find. I mean simple things like explaining what exactly Sections and Categories are supposed to achieve.
Up-to-the-minute hit logs and referrer logs are nice too - but why the heck are they just presented in raw form? I already have that in my web server logs. If I'm storing the hits anyway, I'd expect them to be intelligently filtered - for example, resolving article connections and generating summaries and overviews. Otherwise it's useless.
I couldn't find the bookmarklet that's supposed to be there for one-click adding of links. I find it more practical if something like that is available as a link for drag-and-drop. If I have to search for it somewhere first, it's just inconvenient. Especially since you can't search on the Textpattern homepage. And the documentation doesn't exist anyway, which of course makes searching in it difficult...
And with browser-based plugin installation, I'd expect at least that I can specify not just a file, but also a URL. Because why should I first download a plugin to my hard drive that I'm supposed to install on another website from the web?
The built-in search engine is nice enough for visitors, but it apparently doesn't search in the subject line. Why not? The subject line is predestined for searching.
All in all, Textpattern makes a very strange, unfinished impression on me. Many interesting approaches, but unlike, for example, WordPress, all of them somehow not fully thought through. Only sketched out. A shame, really - because visually Textpattern looks very impressive. WordPress, by comparison, seems downright prudish.