The CSS stylesheet for the changeset view uses grey text. Generally speaking, grey text is often suboptimal from a readability point of view, even though it may look good. However, printing on a budget monochrome laser printer, such as the one I have, makes it even worse; on most monochrome printers, dithering causes anything but black text to be hard to read.
I've attached an example printout from Safari 4 on a Mac. If you're interested, I can try to get a photo of the resulting printout. I'll see if I can dig up an example of a view I tuned for print readability too.