WPF text rendering currently has a complete show-stopper of a problem. I'm not talking about the general "blurriness" of text. That's just anti-aliasing, and while I personally prefer small text to be aliased, I can live with it.
The problem that is driving me mad is the behavior of text when it scrolls. After scrolling stops, sections of the text will slowly adjust focus over a period of a second or two. At first, I thought the issue was just eyestrain on my part, but it really is doing it. It is very uncomfortable to look at, and in my opinion makes WPF useless in text-heavy applications until Microsoft finds a way to fix it.
Other people have noticed the issue as well. This post sheds some light on the issue, and implies that it was a conscious design decision.
There has to be a better way...