Jeroen--
Are you looking at this text on the computer monitor or on an external video monitor?
DV has always been harsh on graphics, especially text, but it might not look as bad as you think it does if you're only using the computer monitor to judge quality.
If you're not using an external moitor, check the manual for a diagram of proper audio and video monitoring techniques. Depending on which version of FCP, it's somewhere in the first 100 or so pages.
If you are using an external monitor, then double check that you are rendering at Full Quality.