All you have to do is change the default fonts to the Liberation font set to experience slightly better looking text within your desktop environment.
Go to KDE System settings > Appearance > Fonts
System Settings - Fonts
Simply match the fonts in the above screenshot, set Anti Aliasing to enabled and the DPI to 96.
Finally click on the configure button and change the font hinting to full.
Once you have finished, reboot for your changes to take effect.