As a layout and rendering toolkit, the modern web browser is just head and shoulders above everything else in terms of features and ease of use.

As problematic as CSS is, getting things in the right place is still dramatically easier than with Swing LayoutManagers, and when you do have problems, you have great tools in the browser to explain what's going on.

Browsers particularly shine in text rendering, naturally; text styling, font selection, word wrapping, etc. are all easily configurable. You want bold text next to regular text in Swing? You either need two JLabels, or you wrap your text in <html> tags and let the embedded HTML 3.2 renderer do it.