Since the current builds of WPF Studio (at the time of this article) are based on .NET 3.5 SP1 and later as minimum requirements, our samples that target .NET 3.5 SP1 cannot show the text rendering improvements that were added to WPF in .NET 4.0. Several customers have looked into WPF and have almost chosen to look at alternate platforms due to the text rendering being too fuzzy for them.
We wanted to point customers to this article that explains new text rendering options added in .NET 4.0 that can dramatically improve text rendering to be as clear as native GDI rendering:
WPF by default will try to render text exactly using the spacing that the font author intended. However this often leads to anti-aliased (blurred) lines. Options added in .NET 4.0 let you tell the WPF text rendering engine to instead render text so that it looks clear on displays.
The article above shows the various options available to you and their result when used. It's easy to configure the options for your application.